- The Iranian Food Science and Technology Research Journal (IFSTRJ) was established in 2005 by Ferdowsi University of M... moreThe Iranian Food Science and Technology Research Journal (IFSTRJ) was established in 2005 by Ferdowsi University of Mashhad with the collaboration of Iranian Food Science and Technology Association (IFSTA) through a bilateral Memorandum of Understanding.
IFSTRJ is a scientific journal and is focused on almost all fields of food science and technology research categorized as Food chemistry, Food physics, Food microbiology and biotechnology, Food technology, and Food engineering. IFSTRJ selects, reviews and publishes articles regarding selected fields of food science and technology research i.e. food chemistry, food physics, food microbiology and biotechnology, food technology, and food process engineering. Sub-disciplines surrounding its scope have been categorized as food rheology, image processing, dairy technology, cereal technology, meat science, food packaging, nano-food technology, food risk assessments, food safety and molecular biology.edit
Introduction Intelligent food packaging as a new technology can maintain the quality and safety of food during its shelf life. This technology uses indicators and sensors that are used in packaging and detects physiological changes in... more
Introduction
Intelligent food packaging as a new technology can maintain the quality and safety of food during its shelf life. This technology uses indicators and sensors that are used in packaging and detects physiological changes in food (due to microbial and chemical degradation). These indicators usually provide information that can be easily identified by the food distributor and the consumer. However, most of the markers currently used are non-renewable and non-degradable synthetic materials. Microalgae that live in both marine and freshwater are a versatile solution for building new biosensors to detect pollutants such as herbicides or heavy metals. These photosynthetic microorganisms are very sensitive to their environmental changes and allow the detection of pollutants. In the past few years, several studies have been conducted in relation to the development, evaluation and application of biosensors using natural compounds in smart food packaging, and some of them are reported and summarized in Table 2.
Materials and Methods
In these studies, examples are mainly focused on biosensors related to biopolymers, but some other synthetic polymers that are easily degraded have also been used as examples. In Table 2, it is also specified what the function and application of the sensor is and how it reacts to the loss of freshness of food. Most sensors are sensitive to the change in pH caused by the release of volatile nitrogen compounds, and this change is characterized by a colorimetric response. Sensors are usually placed in the space above the food container, avoiding direct contact with the food, but close enough to detect changes in the environment and respond to changes in food quality. When these biosensors are integrated with biopolymers, they are usually incorporated into the polymer structure, and the color change of the layers (film) indicates changes in food quality in the packed product. The collected information also clearly shows that extracts rich in chemical compounds of pigments that change color with pH and especially anthocyanins have been used in these biosensors. In addition, most studies of biosensors have been conducted on fish, meat, and seafood, which is probably because their quality degradation is an important economic loss and also because the pH of the surrounding environment is changed during the degradation process. , and this change is easily detected through pH-sensitive biosensors. Smart food packaging technology has made it possible to monitor food quality by incorporating markers, sensors and radio frequency identification (RFID) into packaging. The technology also allows producers and consumers to trace the history of a product through important points in the food supply chain.Interestingly, some compounds applied and tested in the sensor not only provide a pH-sensitive dye, but also have other bioactive properties, for example, antimicrobial properties, and its presence in the polymer matrix can also increase the storage activity of packaging materials.
Results and Discussion
This paper shows that microalgae can be used as biosensors to detect pollutants such as herbicides, heavy metals and volatile organic compounds. These biosensors are very sensitive and reproducible for physical or chemical analysis. One of the main advantages of these microalgal biosensors is that repeated measurements can be performed without extensive sample preparation. They can also be selective, for example chlorophyll fluorescence emitted from photosynthetic activity allows the detection of herbicides, while inhibition of alkaline phosphatase and esterase allows the determination of heavy metals and organophosphate insecticides. Recently, great progress has been made in the identification of genes and related pathways in microalgae, and powerful techniques for genetic engineering have been developed. Collectively, the progress achieved in these areas will rapidly increase our ability to genetically optimize the production of more sensitive microalgae-based biosensors.
Intelligent food packaging as a new technology can maintain the quality and safety of food during its shelf life. This technology uses indicators and sensors that are used in packaging and detects physiological changes in food (due to microbial and chemical degradation). These indicators usually provide information that can be easily identified by the food distributor and the consumer. However, most of the markers currently used are non-renewable and non-degradable synthetic materials. Microalgae that live in both marine and freshwater are a versatile solution for building new biosensors to detect pollutants such as herbicides or heavy metals. These photosynthetic microorganisms are very sensitive to their environmental changes and allow the detection of pollutants. In the past few years, several studies have been conducted in relation to the development, evaluation and application of biosensors using natural compounds in smart food packaging, and some of them are reported and summarized in Table 2.
Materials and Methods
In these studies, examples are mainly focused on biosensors related to biopolymers, but some other synthetic polymers that are easily degraded have also been used as examples. In Table 2, it is also specified what the function and application of the sensor is and how it reacts to the loss of freshness of food. Most sensors are sensitive to the change in pH caused by the release of volatile nitrogen compounds, and this change is characterized by a colorimetric response. Sensors are usually placed in the space above the food container, avoiding direct contact with the food, but close enough to detect changes in the environment and respond to changes in food quality. When these biosensors are integrated with biopolymers, they are usually incorporated into the polymer structure, and the color change of the layers (film) indicates changes in food quality in the packed product. The collected information also clearly shows that extracts rich in chemical compounds of pigments that change color with pH and especially anthocyanins have been used in these biosensors. In addition, most studies of biosensors have been conducted on fish, meat, and seafood, which is probably because their quality degradation is an important economic loss and also because the pH of the surrounding environment is changed during the degradation process. , and this change is easily detected through pH-sensitive biosensors. Smart food packaging technology has made it possible to monitor food quality by incorporating markers, sensors and radio frequency identification (RFID) into packaging. The technology also allows producers and consumers to trace the history of a product through important points in the food supply chain.Interestingly, some compounds applied and tested in the sensor not only provide a pH-sensitive dye, but also have other bioactive properties, for example, antimicrobial properties, and its presence in the polymer matrix can also increase the storage activity of packaging materials.
Results and Discussion
This paper shows that microalgae can be used as biosensors to detect pollutants such as herbicides, heavy metals and volatile organic compounds. These biosensors are very sensitive and reproducible for physical or chemical analysis. One of the main advantages of these microalgal biosensors is that repeated measurements can be performed without extensive sample preparation. They can also be selective, for example chlorophyll fluorescence emitted from photosynthetic activity allows the detection of herbicides, while inhibition of alkaline phosphatase and esterase allows the determination of heavy metals and organophosphate insecticides. Recently, great progress has been made in the identification of genes and related pathways in microalgae, and powerful techniques for genetic engineering have been developed. Collectively, the progress achieved in these areas will rapidly increase our ability to genetically optimize the production of more sensitive microalgae-based biosensors.
Research Interests:
Introduction Seaweeds contain a high amount of protein, essential amino acids, vitamins, minerals, unsaturated fatty acids such as arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), natural pigments, macro and... more
Introduction
Seaweeds contain a high amount of protein, essential amino acids, vitamins, minerals, unsaturated fatty acids such as arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), natural pigments, macro and micro nutrient compounds. Microalgae Spirulina (Spirulina platensis) is a species with high nutritional value. About 60% to 70% of the dry weight (Spirulina platensis) is protein, which has all the essential amino acids. This is a cyanobacterial microalga that is cultivated all over the world and used as a supplement in the human diet in the form of tablets, powder and cookies, bread, salad and soup. Several studies have been conducted in the field of investigating the effect of microalgae addition in food products. The purpose of the current research was to investigate the effect of this microalgae powder on sensory, physical, protein and iron properties of three different products of bulk bread, cake and layered sweets with different formulations.
Materials and Methods
Spirulina microalgae dry powder in 0.25%, 0.5%, 0.75%, 1% and 1.25% was added to the formula of three products: bulk bread, layered pastry, and cake. From each product, a sample without microalgae powder was also prepared and considered as a control. The treatments were evaluated in terms of sensory, color, texture, protein and iron content. Sensory evaluation was carried out by 30 panelists using 7 hedonic points to evaluate the color, flavor, texture, smell and overall acceptance. The color of the surface of the samples was done with a Minolta Chroma Meter (CR-300 Minolta Japan). The results calculated based on L* (whiteness/darkness), a*(redness/greenness) and b*(blueness/yellowness). Hardness of samples was measured with Texture Analyzer TA-XT2 (Stable Micro Systems, Surrey, England) and P/0.5 cylindrical probe (12.5 mm diameter) with 30 kg load cell. Protein of the samples was measured by Kjeldahl method and the amount of iron was measured according to the standard method of AOAC 999.11. All analyses were performed in three repetitions and one-way ANOVA and Tukey's test were used to compare the means.
Results and Discussion
The results showed that the behavior of spirulina microalgae in changing the characteristics of the three products is different, and this difference is especially significant in sensory characteristics. The addition of spirulina microalgae increased the amount of protein and iron in different treatments. This increase for protein in bread, cake and sweets was about 1, 0.6 and 1.2 percent, respectively. Also, the amount of iron in treatments containing microalgae in bread, cake, and layered sweets was 4, 5, and 3 mg/kg, respectively. Spirulina microalgae is basically known as an aquatic plant with high protein and iron. The microalgae used in this research contained a high amount of protein (67.97%) and 29.5 mg/100 grams of iron, so adding this microalga to the samples increased the amount of protein and iron. Sensory evaluation of the samples showed that all three products had an acceptable acceptance score. However, in comparison among the three products of bread, cake and layered sweets, bread had a lower score than the other two products. The instrumental analysis of L*, a*, b* color indices showed that the increase of spirulina caused green color in the treatments and this color change is more significant in the bread sample. Also, the results of texture analysis showed that the addition of spirulina reduces the hardness of samples containing spirulina. It can be concluded that spirulina microalgae can be used to improve texture, color, and also increase the amount of protein and iron in products.
Seaweeds contain a high amount of protein, essential amino acids, vitamins, minerals, unsaturated fatty acids such as arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), natural pigments, macro and micro nutrient compounds. Microalgae Spirulina (Spirulina platensis) is a species with high nutritional value. About 60% to 70% of the dry weight (Spirulina platensis) is protein, which has all the essential amino acids. This is a cyanobacterial microalga that is cultivated all over the world and used as a supplement in the human diet in the form of tablets, powder and cookies, bread, salad and soup. Several studies have been conducted in the field of investigating the effect of microalgae addition in food products. The purpose of the current research was to investigate the effect of this microalgae powder on sensory, physical, protein and iron properties of three different products of bulk bread, cake and layered sweets with different formulations.
Materials and Methods
Spirulina microalgae dry powder in 0.25%, 0.5%, 0.75%, 1% and 1.25% was added to the formula of three products: bulk bread, layered pastry, and cake. From each product, a sample without microalgae powder was also prepared and considered as a control. The treatments were evaluated in terms of sensory, color, texture, protein and iron content. Sensory evaluation was carried out by 30 panelists using 7 hedonic points to evaluate the color, flavor, texture, smell and overall acceptance. The color of the surface of the samples was done with a Minolta Chroma Meter (CR-300 Minolta Japan). The results calculated based on L* (whiteness/darkness), a*(redness/greenness) and b*(blueness/yellowness). Hardness of samples was measured with Texture Analyzer TA-XT2 (Stable Micro Systems, Surrey, England) and P/0.5 cylindrical probe (12.5 mm diameter) with 30 kg load cell. Protein of the samples was measured by Kjeldahl method and the amount of iron was measured according to the standard method of AOAC 999.11. All analyses were performed in three repetitions and one-way ANOVA and Tukey's test were used to compare the means.
Results and Discussion
The results showed that the behavior of spirulina microalgae in changing the characteristics of the three products is different, and this difference is especially significant in sensory characteristics. The addition of spirulina microalgae increased the amount of protein and iron in different treatments. This increase for protein in bread, cake and sweets was about 1, 0.6 and 1.2 percent, respectively. Also, the amount of iron in treatments containing microalgae in bread, cake, and layered sweets was 4, 5, and 3 mg/kg, respectively. Spirulina microalgae is basically known as an aquatic plant with high protein and iron. The microalgae used in this research contained a high amount of protein (67.97%) and 29.5 mg/100 grams of iron, so adding this microalga to the samples increased the amount of protein and iron. Sensory evaluation of the samples showed that all three products had an acceptable acceptance score. However, in comparison among the three products of bread, cake and layered sweets, bread had a lower score than the other two products. The instrumental analysis of L*, a*, b* color indices showed that the increase of spirulina caused green color in the treatments and this color change is more significant in the bread sample. Also, the results of texture analysis showed that the addition of spirulina reduces the hardness of samples containing spirulina. It can be concluded that spirulina microalgae can be used to improve texture, color, and also increase the amount of protein and iron in products.
Research Interests:
Introduction Caffeine is one of the most common bioactive compounds in the world that can enhance mental and physical performance However its bitter taste has created challenges for the use of this compound in food. Nano-encapsulation... more
Introduction
Caffeine is one of the most common bioactive compounds in the world that can enhance mental and physical performance However its bitter taste has created challenges for the use of this compound in food. Nano-encapsulation technology, such as the use of liposomes, is one of the simplest ways to overcome this issue. In this research, caffeine was encapsulated in nanoliposomes coated with chitosan and then the drink powder enriched with caffeine nanochitosome was produced.
Materials and methods
In this research, pure caffeine powder was purchased and stored in dry environment at room temperature. Ethanol (96%) and acetic acid were obtained from Mojallali Company, Tween 80 from Merck Company (Germany), lecithin (P3556), cholesterol (C8667), and chitosan (medium molecular weight) purchased from Sigma Aldrich Company (Germany). Sugar, essential oil and citric acid used in the formulation of the drink were purchased from a local store.
First, nanochitosomes in ratios of 9:1, 8:2 and 7:3 lecithin-cholesterol, were prepared using thin-layer hydration method. Then, the particle size and zeta potential were measured to determine the characteristics of the produced particles. Encapsulation efficiency was measured for 9:1, 8:2 and 7:3 lecithin-cholesterol ratios. The stability of the chitosomal sample with a ratio of 9:1 lecithin-cholesterol was evaluated through visual observation of precipitation formation and the amount of release of encapsulated caffeine during 60 days of storage at ambient temperature was calculated. FTIR was performed for each of the components of the wall of chitosomes, caffeine powder, chitosomal solution containing caffeine and chitosomal solution without caffeine with a ratio of 9:1 lecithin-cholesterol. Nanochitosomes with 9:1 lecithin-cholesterol ratio were used in the formulation of beverages due to having the smallest particle size, favorable zeta potential, the highest microencapsulation efficiency, and high stability during storage. The drink samples were prepared in different formulations (samples containing 3 and 5% free caffeine solution, samples containing 3 and 5% chitosomal caffeine solution and the control sample). Then, the drinks were evaluated in terms of sensory characteristics and other physico-chemical characteristics (pH, acidity, Brix degree, etc.). The drinks produced were turned into powder with a freeze-dryer machine, and two important characteristics of powdered products, i.e. water solubility index and their hygroscopicity, were evaluated.
Results and Discussion
The average particle size and zeta potential for different ratios of lecithin -cholesterol were obtained in the range of 133.3-443.6 nm and +40.96 to +48.36, respectively. The encapsulation efficiency for 9:1, 8:2 and 7:3 lecithin-cholesterol ratios were 91.2%, 86.18% and 79.09 %, respectively. The chitosomal sample with 9:1 lecithin-cholesterol ratio showed good stability during 60 days of storage at ambient temperature. FTIR results showed that caffeine was loaded in nanochitosomes. The results of the sensory evaluation of the prepared beverages showed the acceptability of the taste of the samples containing caffeine nanochitosome compared to the samples containing free caffeine, which indicates the success of chitosomal nanocarriers in covering the bitter taste of caffeine. The results of measuring the color of different drink samples showed that there is no significant difference between the color of samples. The results of measuring pH and acidity did not show significant differences between different drink samples. The results of measuring the solubility of different drink powder samples showed that the samples containing caffeine nanochitosomes have low solubility compared to other drink powder samples. Also, the hygroscopic amount of the drink powder containing caffeine nanochitosomes was lower than the other samples, which is considered as an advantage for powdered products.
The results obtained in this research showed that nanochitosomes are an efficient system in covering the bitter taste of caffeine. Therefore, with the production of caffeine nanochitosomes and its usage in the formulation of powder drinks, it is possible to produce energizing and desirable drinks without the need to use high amounts of sucrose.
Caffeine is one of the most common bioactive compounds in the world that can enhance mental and physical performance However its bitter taste has created challenges for the use of this compound in food. Nano-encapsulation technology, such as the use of liposomes, is one of the simplest ways to overcome this issue. In this research, caffeine was encapsulated in nanoliposomes coated with chitosan and then the drink powder enriched with caffeine nanochitosome was produced.
Materials and methods
In this research, pure caffeine powder was purchased and stored in dry environment at room temperature. Ethanol (96%) and acetic acid were obtained from Mojallali Company, Tween 80 from Merck Company (Germany), lecithin (P3556), cholesterol (C8667), and chitosan (medium molecular weight) purchased from Sigma Aldrich Company (Germany). Sugar, essential oil and citric acid used in the formulation of the drink were purchased from a local store.
First, nanochitosomes in ratios of 9:1, 8:2 and 7:3 lecithin-cholesterol, were prepared using thin-layer hydration method. Then, the particle size and zeta potential were measured to determine the characteristics of the produced particles. Encapsulation efficiency was measured for 9:1, 8:2 and 7:3 lecithin-cholesterol ratios. The stability of the chitosomal sample with a ratio of 9:1 lecithin-cholesterol was evaluated through visual observation of precipitation formation and the amount of release of encapsulated caffeine during 60 days of storage at ambient temperature was calculated. FTIR was performed for each of the components of the wall of chitosomes, caffeine powder, chitosomal solution containing caffeine and chitosomal solution without caffeine with a ratio of 9:1 lecithin-cholesterol. Nanochitosomes with 9:1 lecithin-cholesterol ratio were used in the formulation of beverages due to having the smallest particle size, favorable zeta potential, the highest microencapsulation efficiency, and high stability during storage. The drink samples were prepared in different formulations (samples containing 3 and 5% free caffeine solution, samples containing 3 and 5% chitosomal caffeine solution and the control sample). Then, the drinks were evaluated in terms of sensory characteristics and other physico-chemical characteristics (pH, acidity, Brix degree, etc.). The drinks produced were turned into powder with a freeze-dryer machine, and two important characteristics of powdered products, i.e. water solubility index and their hygroscopicity, were evaluated.
Results and Discussion
The average particle size and zeta potential for different ratios of lecithin -cholesterol were obtained in the range of 133.3-443.6 nm and +40.96 to +48.36, respectively. The encapsulation efficiency for 9:1, 8:2 and 7:3 lecithin-cholesterol ratios were 91.2%, 86.18% and 79.09 %, respectively. The chitosomal sample with 9:1 lecithin-cholesterol ratio showed good stability during 60 days of storage at ambient temperature. FTIR results showed that caffeine was loaded in nanochitosomes. The results of the sensory evaluation of the prepared beverages showed the acceptability of the taste of the samples containing caffeine nanochitosome compared to the samples containing free caffeine, which indicates the success of chitosomal nanocarriers in covering the bitter taste of caffeine. The results of measuring the color of different drink samples showed that there is no significant difference between the color of samples. The results of measuring pH and acidity did not show significant differences between different drink samples. The results of measuring the solubility of different drink powder samples showed that the samples containing caffeine nanochitosomes have low solubility compared to other drink powder samples. Also, the hygroscopic amount of the drink powder containing caffeine nanochitosomes was lower than the other samples, which is considered as an advantage for powdered products.
The results obtained in this research showed that nanochitosomes are an efficient system in covering the bitter taste of caffeine. Therefore, with the production of caffeine nanochitosomes and its usage in the formulation of powder drinks, it is possible to produce energizing and desirable drinks without the need to use high amounts of sucrose.
Research Interests:
Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the... more
Introduction
The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute water, soil, plants, and eventually foodstuffs and our bodies. Several methods exist to remediate heavy metal pollution in waters such as membrane filtration, ion exchange mechanisms, or by precipitation. Yet, these techniques are not cost effective, in some cases, and do produce wastes that need to be properly disposed of. Microbial bioremediation could be an alternative. The use of microbes for remediation of heavy metals has been well studied. Some microorganisms, especially soil bacteria, have the ability to tolerate these contaminants. In addition, certain bacterial strains are capable of binding to heavy metals or transforming them into less toxic forms. Low operating costs, usable in foodstuffs, selective removal for specific toxic metals, minimal use of chemicals (resulting in low sludge production) and high efficiencies at very low levels of heavy metals are some of the advantages of biosorption methods. In this regard, the purpose of this study was to investigate the ability of active and passive absorption of heavy metals by a number of Lactic Acid Bacteria (LAB) strains in laboratory environment and food.
Materials and Methods
Seven LAB isolates including Lacticaseibacillus casei (RTCC 1296-3), Lacticaseibacillus rhamnosus (RTCC 1293-2), Lactiplantibacillus plantarum (RTCC 1290), Limosilactobacillus fermentum (RTCC 1303), Enterococcus faecium (RTCC 2347), Lactobacillus helveticus (RTCC 1304) and Lactobacillus acidophilus (RTCC 1299) were obtained from Razi type culture collection (RTCC), located at Razi vaccine and Serum Research Institute, Iran. All isolates were cultured in MRS (Scharlau, Spain) broth medium, at 37 °C for 24 hours, under anaerobic conditions. Pure cultures were preserved for long term by freezing at -70°C with 20% Glycerol. Heavy metals including Nitrate of Pb (II), Cd (II) and Ni (II) were purchased from Merck (Darmstadt, Germany). All standard solutions were prepared from the stock solutions containing 1000 mgl-1 in distilled water. Other chemicals used in study including Nitric acid (65%) and Hydrogen peroxide (37%), were also purchased from Merck, Germany. This study was conducted in two in- vitro and in-vivo phases; in the in- vitro phase, seven strains of bacteria with probiotic properties (L. casei, L. rhamnosus, L. plantarum, L. fermentum, Ent. facium, L. helveticus and L. acidofilous) were screened and then their ability to bind to cadmium (Cd), Lead (Pb) and nickel (Ni) in aqueous solution was investigated. Then, in the in-vivo stage, three probiotic strains that had the highest biosorption efficiency in the previously stage were selected and their effect with a ratio of 1:1:1 and contact time of 15 and 30 minutes on the removal of these toxic metals in coriander, leek and parsley fresh vegetables was evaluated. The residual concentrations of heavy metals in solution were measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS; ELAN DRC-e, PerkinElmer SCIEX, Canada) and Morphology of bacteria cell surfaces incubated with metals were monitored by scanning electron microscopy (JEOL JSM 5400 LV, Japan).
Results and Discussion
The results of the in vitro stage showed that the most ability to heavy metals adsorption was related to the Ent. Facium bacterium which were equal to 79.75±0.11, 75.28±0.05 and 83.99±0.10% for Pb, Cd and Ni, respectively. In general, the removal efficiency of heavy metals by LAB bacteria in the inactive and killed state was significantly higher than the active removal efficiency of these bacteria, so that the highest percentage of passive absorption of lead, cadmium and nickel metals by inactive strains of L. casei, L. plantarum and Ent. Facium were 90.01, 81.98 and 86.56%, respectively. Electron microscopy observations and energy dispersive X-ray (EDX) analysis confirmed that the majority of these toxic metals significantly damage the surface of living cells by accumulating and binding on the surface of bacterial cells. A combination of three bacterial strains had a synergistic effect on the binding properties of toxic metals compared to the single state of these bacteria, so that in both active and inactive states, 90-99% of heavy metals from edible leafy vegetables were removed in less than 15 minutes. The results of this research generally showed that the binding capacity of dead biomass is significantly high and it is possible to dispose and reuse biomass in case of biological absorption.
The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute water, soil, plants, and eventually foodstuffs and our bodies. Several methods exist to remediate heavy metal pollution in waters such as membrane filtration, ion exchange mechanisms, or by precipitation. Yet, these techniques are not cost effective, in some cases, and do produce wastes that need to be properly disposed of. Microbial bioremediation could be an alternative. The use of microbes for remediation of heavy metals has been well studied. Some microorganisms, especially soil bacteria, have the ability to tolerate these contaminants. In addition, certain bacterial strains are capable of binding to heavy metals or transforming them into less toxic forms. Low operating costs, usable in foodstuffs, selective removal for specific toxic metals, minimal use of chemicals (resulting in low sludge production) and high efficiencies at very low levels of heavy metals are some of the advantages of biosorption methods. In this regard, the purpose of this study was to investigate the ability of active and passive absorption of heavy metals by a number of Lactic Acid Bacteria (LAB) strains in laboratory environment and food.
Materials and Methods
Seven LAB isolates including Lacticaseibacillus casei (RTCC 1296-3), Lacticaseibacillus rhamnosus (RTCC 1293-2), Lactiplantibacillus plantarum (RTCC 1290), Limosilactobacillus fermentum (RTCC 1303), Enterococcus faecium (RTCC 2347), Lactobacillus helveticus (RTCC 1304) and Lactobacillus acidophilus (RTCC 1299) were obtained from Razi type culture collection (RTCC), located at Razi vaccine and Serum Research Institute, Iran. All isolates were cultured in MRS (Scharlau, Spain) broth medium, at 37 °C for 24 hours, under anaerobic conditions. Pure cultures were preserved for long term by freezing at -70°C with 20% Glycerol. Heavy metals including Nitrate of Pb (II), Cd (II) and Ni (II) were purchased from Merck (Darmstadt, Germany). All standard solutions were prepared from the stock solutions containing 1000 mgl-1 in distilled water. Other chemicals used in study including Nitric acid (65%) and Hydrogen peroxide (37%), were also purchased from Merck, Germany. This study was conducted in two in- vitro and in-vivo phases; in the in- vitro phase, seven strains of bacteria with probiotic properties (L. casei, L. rhamnosus, L. plantarum, L. fermentum, Ent. facium, L. helveticus and L. acidofilous) were screened and then their ability to bind to cadmium (Cd), Lead (Pb) and nickel (Ni) in aqueous solution was investigated. Then, in the in-vivo stage, three probiotic strains that had the highest biosorption efficiency in the previously stage were selected and their effect with a ratio of 1:1:1 and contact time of 15 and 30 minutes on the removal of these toxic metals in coriander, leek and parsley fresh vegetables was evaluated. The residual concentrations of heavy metals in solution were measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS; ELAN DRC-e, PerkinElmer SCIEX, Canada) and Morphology of bacteria cell surfaces incubated with metals were monitored by scanning electron microscopy (JEOL JSM 5400 LV, Japan).
Results and Discussion
The results of the in vitro stage showed that the most ability to heavy metals adsorption was related to the Ent. Facium bacterium which were equal to 79.75±0.11, 75.28±0.05 and 83.99±0.10% for Pb, Cd and Ni, respectively. In general, the removal efficiency of heavy metals by LAB bacteria in the inactive and killed state was significantly higher than the active removal efficiency of these bacteria, so that the highest percentage of passive absorption of lead, cadmium and nickel metals by inactive strains of L. casei, L. plantarum and Ent. Facium were 90.01, 81.98 and 86.56%, respectively. Electron microscopy observations and energy dispersive X-ray (EDX) analysis confirmed that the majority of these toxic metals significantly damage the surface of living cells by accumulating and binding on the surface of bacterial cells. A combination of three bacterial strains had a synergistic effect on the binding properties of toxic metals compared to the single state of these bacteria, so that in both active and inactive states, 90-99% of heavy metals from edible leafy vegetables were removed in less than 15 minutes. The results of this research generally showed that the binding capacity of dead biomass is significantly high and it is possible to dispose and reuse biomass in case of biological absorption.
Research Interests:
Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C).... more
Introduction
Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation.
Materials and Methods
In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level.
Results and Discussion
The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05).
Conclusion
According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation.
Materials and Methods
In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level.
Results and Discussion
The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05).
Conclusion
According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Research Interests:
Introduction Thermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In... more
Introduction
Thermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In addition, a better understanding of the mechanism of the heating process will lead to an improved performance in the process and to some energy savings (Abdul Ghani et al., 1999). Computational fluid dynamics (CFD) is an efficient way to study flow behavior and temperature distribution of thermal processing in the food technology (Ghani et al., 2003). As the semi-rigid aluminum packaging market recently has been introduced, there is limited information about the temperature distribution during the heating process of such containers. In this paper the temperature distribution was predicted and location of cold zone was determined. The effect of headspace (air and water vapor) in heat transfer mechanism was investigated.
Materials and Methods
Physical properties
Malt extract properties such as density, specific heat, thermal conductivity and viscosity values are necessary for the equations solution. Viscosity and density of the sample was measured as a function of temperature (Vatankhah et al., 2015). Specific heat and thermal conductivity of sample were estimated using the mass fraction of its constituents. For simulation, the experimental results were applied by piecewise-linear method in the material part of the software to describe viscosity, thermal conductivity and specific heat.
Experimental methodology
For the experimental, a thermocouple probe was located at point (0, 0, -2.76) in a semi rigid aluminum based packaging to measure the temperature distribution inside the container. Then the package was filled with malt extract (°Brix ~ 60) and then the package was sealed at 280 °C using Alcan machine. Another thermocouple was placed near the containers, in the water cascading Barriquand steriflow retort. The thermocouples were attached to Ellab data logger by PT100 cables. The data logger was connected to a personal computer and E-val 2.1 software was used to export time temperature profile of each thermocouple in 1 min intervals.
Geometry and meshing
Gambit 2.3.30 was used to develop geometry and set of grid (0.2 cm, and 0.1 cm mesh size) was performed. Then software of fluent 6.3.26 with 3-D, double precision, pressure-based solver, implicit formulation, unsteady time, laminar flow was applied to solve the system of the governing equations (Vatankhah et al., 2015).
Boundary conditions and initial values
Unsteady temperature function was imposed to all faces of the geometry in 1 min time intervals. No-slip boundary condition was supposed for velocity components relative to boundaries. The boundary conditions used at top surface, bottom surface and side walls included: T = Tw, Vx = 0, Vy = 0 and Vz = 0. The initial temperature was assumed as the first temperature which was measured by the thermocouple at the starting time of processing.
Solution methodology
Fluent software was used to solve the Navier-Stokes and energy equations simultaneously. A preset convergence limit of 10−3 for continuity and momentum equations and 10−8 for the energy equation were used, in order to achieve an appropriate convergence. The under-relaxation factors were adjusted smaller than 1 to obtain a good convergence of the numerical solution. SIMPLEC algorithm was used for pressure-velocity coupling.
Results and Discussion
There was no significant difference between predicted and experimental temperatures for point (0, 0, -2.76) in models with and without head space using t-test (p<0.01). Temperature contours of predicted models (with headspace) were similar to model without headspace at the different stages of the process. Simulation result showed slowest heating zone located in (0.02 <X< 0.8, -1 <Y< 0.3 and -3.27<Z< 3.27) for model of malt extract with headspace and in (-3.58 < X< 3.76, -3.44 <Y< 0.48 and -3.46 <Z< -3.05) for model of malt extract without headspace.
Conclusion
The heating process of malt extract in semi rigid aluminum container during thermal processing was simulated successfully using CFD. The CFD based model showed that the position of SHZ was located in the third end of the container.
Thermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In addition, a better understanding of the mechanism of the heating process will lead to an improved performance in the process and to some energy savings (Abdul Ghani et al., 1999). Computational fluid dynamics (CFD) is an efficient way to study flow behavior and temperature distribution of thermal processing in the food technology (Ghani et al., 2003). As the semi-rigid aluminum packaging market recently has been introduced, there is limited information about the temperature distribution during the heating process of such containers. In this paper the temperature distribution was predicted and location of cold zone was determined. The effect of headspace (air and water vapor) in heat transfer mechanism was investigated.
Materials and Methods
Physical properties
Malt extract properties such as density, specific heat, thermal conductivity and viscosity values are necessary for the equations solution. Viscosity and density of the sample was measured as a function of temperature (Vatankhah et al., 2015). Specific heat and thermal conductivity of sample were estimated using the mass fraction of its constituents. For simulation, the experimental results were applied by piecewise-linear method in the material part of the software to describe viscosity, thermal conductivity and specific heat.
Experimental methodology
For the experimental, a thermocouple probe was located at point (0, 0, -2.76) in a semi rigid aluminum based packaging to measure the temperature distribution inside the container. Then the package was filled with malt extract (°Brix ~ 60) and then the package was sealed at 280 °C using Alcan machine. Another thermocouple was placed near the containers, in the water cascading Barriquand steriflow retort. The thermocouples were attached to Ellab data logger by PT100 cables. The data logger was connected to a personal computer and E-val 2.1 software was used to export time temperature profile of each thermocouple in 1 min intervals.
Geometry and meshing
Gambit 2.3.30 was used to develop geometry and set of grid (0.2 cm, and 0.1 cm mesh size) was performed. Then software of fluent 6.3.26 with 3-D, double precision, pressure-based solver, implicit formulation, unsteady time, laminar flow was applied to solve the system of the governing equations (Vatankhah et al., 2015).
Boundary conditions and initial values
Unsteady temperature function was imposed to all faces of the geometry in 1 min time intervals. No-slip boundary condition was supposed for velocity components relative to boundaries. The boundary conditions used at top surface, bottom surface and side walls included: T = Tw, Vx = 0, Vy = 0 and Vz = 0. The initial temperature was assumed as the first temperature which was measured by the thermocouple at the starting time of processing.
Solution methodology
Fluent software was used to solve the Navier-Stokes and energy equations simultaneously. A preset convergence limit of 10−3 for continuity and momentum equations and 10−8 for the energy equation were used, in order to achieve an appropriate convergence. The under-relaxation factors were adjusted smaller than 1 to obtain a good convergence of the numerical solution. SIMPLEC algorithm was used for pressure-velocity coupling.
Results and Discussion
There was no significant difference between predicted and experimental temperatures for point (0, 0, -2.76) in models with and without head space using t-test (p<0.01). Temperature contours of predicted models (with headspace) were similar to model without headspace at the different stages of the process. Simulation result showed slowest heating zone located in (0.02 <X< 0.8, -1 <Y< 0.3 and -3.27<Z< 3.27) for model of malt extract with headspace and in (-3.58 < X< 3.76, -3.44 <Y< 0.48 and -3.46 <Z< -3.05) for model of malt extract without headspace.
Conclusion
The heating process of malt extract in semi rigid aluminum container during thermal processing was simulated successfully using CFD. The CFD based model showed that the position of SHZ was located in the third end of the container.
Research Interests:
Introduction In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat... more
Introduction
In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat foods. Scientific researchers have provided a great quantity of evidence between the consumption of high-fat products and the development of diseases such as obesity, hardening of the arteries, chronic hypertension, etc. Fat removal is not an easy task because fat, in addition to nutritional aspects, affect rheological and sensory properties such as mouth feel and texture properties of the final product. Using alternative materials that can be completely or partially replaced fat in the formulation of low-fat products by imitating the properties of fat is great important. Unlike fat, which its high consumption causes many problems; fiber can play a vital role in many of the nutritional, functional, and sensory properties of food products, Some types of fiber act as fat substitutes, while producing less energy, provide a large effect of fat function properties. Increasing consumption of easy-cook meat products such as sausages induced replacement the fat content in the formulation of these products, by fat substitutes such as maltodextrin. The aim of this study was to evaluate the chemical and sensory properties of low fat German sausages produced by maltodextrin.
Materials and Methods
In this study, 0, 6, 12, and 18% of fat was replaced by maltodextrin in the formulation of German sausage. The chemical and sensory properties were then investigated. Chemical properties including moisture, protein, ash, and fat were accomplished according to the ISIRI standard. Evaluation of sensory properties was done by 5-point hedonic method according to Click et al. (2006). Data analysis was performed using SPSS software in a completely randomized design with a 95% confidence level.
Results and Discussion
The results showed that with increasing the level of maltodextrin, the amount of moisture, ash, and starch of sausage samples increased significantly. As the concentration of maltodextrin increased, the protein content of the samples decreased. The highest protein content observed in the control sample and the sample contained 6% maltodextrin and in contrary, the lowest protein content was in the sample containing 18% maltodextrin and there was no statistically significant difference between the test samples (p>0.05). Changes in maltodextrin concentrations had a significant effect on the fat content of sausage samples so that with increasing the concentration of maltodextrin in the sausage formulation, the fat content of the samples decreased (p≤0.05). Also, with increasing the percentage of maltodextrin replacement in German sausage samples, the cooking yield decreased significantly (p≤0.05). In the evaluation of sensory properties, it was found that the use of maltodextrin reduced the score in all parameters studied so that the lowest score in terms of color, texture, flavor, and total acceptance of sausage samples was related to sample with 18% maltodextrin replacement.
Conclusion
The vital role of the effect of dietary fiber on improving and managing the health has been proven by researchers for many years. Due to the need to reduce fat in products such as sausages, which considered as a popular meat product and based on the results observed in the present study, it is recommended to use maltodextrin fiber at the level of 6% as a fat substitute in the formulation of German sausages.
In recent years, increasing consumer awareness of the dangers of consuming high-fat products, sensitivity to proper nutritional patterns and the impact of health factors has increased consumer demand for low-fat or free-fat foods. Scientific researchers have provided a great quantity of evidence between the consumption of high-fat products and the development of diseases such as obesity, hardening of the arteries, chronic hypertension, etc. Fat removal is not an easy task because fat, in addition to nutritional aspects, affect rheological and sensory properties such as mouth feel and texture properties of the final product. Using alternative materials that can be completely or partially replaced fat in the formulation of low-fat products by imitating the properties of fat is great important. Unlike fat, which its high consumption causes many problems; fiber can play a vital role in many of the nutritional, functional, and sensory properties of food products, Some types of fiber act as fat substitutes, while producing less energy, provide a large effect of fat function properties. Increasing consumption of easy-cook meat products such as sausages induced replacement the fat content in the formulation of these products, by fat substitutes such as maltodextrin. The aim of this study was to evaluate the chemical and sensory properties of low fat German sausages produced by maltodextrin.
Materials and Methods
In this study, 0, 6, 12, and 18% of fat was replaced by maltodextrin in the formulation of German sausage. The chemical and sensory properties were then investigated. Chemical properties including moisture, protein, ash, and fat were accomplished according to the ISIRI standard. Evaluation of sensory properties was done by 5-point hedonic method according to Click et al. (2006). Data analysis was performed using SPSS software in a completely randomized design with a 95% confidence level.
Results and Discussion
The results showed that with increasing the level of maltodextrin, the amount of moisture, ash, and starch of sausage samples increased significantly. As the concentration of maltodextrin increased, the protein content of the samples decreased. The highest protein content observed in the control sample and the sample contained 6% maltodextrin and in contrary, the lowest protein content was in the sample containing 18% maltodextrin and there was no statistically significant difference between the test samples (p>0.05). Changes in maltodextrin concentrations had a significant effect on the fat content of sausage samples so that with increasing the concentration of maltodextrin in the sausage formulation, the fat content of the samples decreased (p≤0.05). Also, with increasing the percentage of maltodextrin replacement in German sausage samples, the cooking yield decreased significantly (p≤0.05). In the evaluation of sensory properties, it was found that the use of maltodextrin reduced the score in all parameters studied so that the lowest score in terms of color, texture, flavor, and total acceptance of sausage samples was related to sample with 18% maltodextrin replacement.
Conclusion
The vital role of the effect of dietary fiber on improving and managing the health has been proven by researchers for many years. Due to the need to reduce fat in products such as sausages, which considered as a popular meat product and based on the results observed in the present study, it is recommended to use maltodextrin fiber at the level of 6% as a fat substitute in the formulation of German sausages.
Research Interests:
Introduction Appropriate and effective decolorization of raw and thin juice in sugar refineries is considered as an important process to obtain premium quality sugar, which due to the problems of its conventional process, membrane... more
Introduction
Appropriate and effective decolorization of raw and thin juice in sugar refineries is considered as an important process to obtain premium quality sugar, which due to the problems of its conventional process, membrane processes as effective and environmentally friendly processes can be used in parts of sugar industries. Among the disadvantages of the usual methods to remove membrane fouling, it can be mentioned the destruction of the membrane, environmental pollution, the remaining detergents in the membrane and the product, especially in the pharmaceutical and food industries, and the increase in production costs. Therefore, it seems that physical methods such as pre-filtration of the incoming feed, using turbulent and pulse currents to prevent excessive compression of the gel layer formed on the membrane surface are more effective and have fewer disadvantages. One of the ways to change the flow of feed entering the membrane surface is bubbling, which causes mixing the flow and increases the tangential shear stress. In fact, the hydrodynamic force that creates bubbles causes both the dragging force and the lifting force and leads to the removal of fouling and reducing the phenomenon of concentration polarization.
Materials and Methods
In this research, an ultrafiltration membrane (MWCO=10 KDa) pilot with a flat module (effective surface 40 square centimeters) was used to purify raw beet juice (which had passed a stage of pre-treatment with microfiltration) at the temperature of about 30 degrees Celsius and a trans membrane pressure of 3.5 bar during the process. Nitrogen gas in the amount of 0.5, 1 and 1.5 liters per minute was used in two continuous and interrupted modes for bubbling. In this way, in the interrupted mode, after every 3 minutes of filtration, the filtration process was carried out with gas for one minute. The factors such as flux, fouling and membrane resistance as membrane efficiency's factors and parameters like color, purity and turbidity as purification factors was investigated in the form of a completely random design and compared with control filtration conditions (without bubble generation). The results of this research were statistically analyzed using SAS (version 1.9) and Microsoft Office Excel 2019 software. The average data of each test in three repetitions was compared with the least significant difference (LSD) test at the 95% level.
Results and Discussion
Increasing the amount of gas during the bubbling process improved the flow rate. Also, the results showed that the decreasing trend of the permeate flux at the gassing rate of 1.5 L/min was less than other treatments and more stable conditions were seen in the sap flux during the process. Also, the amount of flux in the interrupted form of bubbling showed that after the application of bubbling, although the amount of flux increased, but after that, during the ultra-refining process, the flux decreased again and did not remain constant at that level. But in general, despite the fact that the average flux was higher in the continuous process compared to the interrupted state, there was no significant difference between them. The results related to the amount of membrane fouling after applying the process showed that by applying bubble generation in both continuous and interrupted mods, the fouling was significantly reduced compared to the usual state of ultrafiltration. Also, as the amount of gas entering the feed stream increased, the membrane fouling decreased, which was slightly higher in the continuous state than in the interrupted mod. The overall hydrodynamic resistance of the membrane in different filtration modes showed that the difference between the overall resistance of the membrane in the ultrafiltration and the ultrafiltration process with gasification is quite significant. However, although the overall resistance of the membrane in the interrupted gassing state is higher than its continuous state due to more clogging, there is no significant difference between them (P<0.05).Since the flux changes and the amount of gel layer formation affect the properties of the purified syrup, the properties of the syrup were also investigated in the best flux created in two continuous and interrupted modes. The results showed that the continuous flow of gasification caused a small defect in the purification properties such as purity, color and turbidity due to the improvement of the permeate flow flux, which of course can be ignored in the sugar industry due to the improvement of the permeate flow flux.
Conclusion
Therefore, in general, it can be said that the discontinuous method, due to less gas consumption during bubbling and no significant difference in the amount of flux compared to the continuous mode, can be considered as the optimal mode of gasification during the experiments conducted in this research be placed.
Appropriate and effective decolorization of raw and thin juice in sugar refineries is considered as an important process to obtain premium quality sugar, which due to the problems of its conventional process, membrane processes as effective and environmentally friendly processes can be used in parts of sugar industries. Among the disadvantages of the usual methods to remove membrane fouling, it can be mentioned the destruction of the membrane, environmental pollution, the remaining detergents in the membrane and the product, especially in the pharmaceutical and food industries, and the increase in production costs. Therefore, it seems that physical methods such as pre-filtration of the incoming feed, using turbulent and pulse currents to prevent excessive compression of the gel layer formed on the membrane surface are more effective and have fewer disadvantages. One of the ways to change the flow of feed entering the membrane surface is bubbling, which causes mixing the flow and increases the tangential shear stress. In fact, the hydrodynamic force that creates bubbles causes both the dragging force and the lifting force and leads to the removal of fouling and reducing the phenomenon of concentration polarization.
Materials and Methods
In this research, an ultrafiltration membrane (MWCO=10 KDa) pilot with a flat module (effective surface 40 square centimeters) was used to purify raw beet juice (which had passed a stage of pre-treatment with microfiltration) at the temperature of about 30 degrees Celsius and a trans membrane pressure of 3.5 bar during the process. Nitrogen gas in the amount of 0.5, 1 and 1.5 liters per minute was used in two continuous and interrupted modes for bubbling. In this way, in the interrupted mode, after every 3 minutes of filtration, the filtration process was carried out with gas for one minute. The factors such as flux, fouling and membrane resistance as membrane efficiency's factors and parameters like color, purity and turbidity as purification factors was investigated in the form of a completely random design and compared with control filtration conditions (without bubble generation). The results of this research were statistically analyzed using SAS (version 1.9) and Microsoft Office Excel 2019 software. The average data of each test in three repetitions was compared with the least significant difference (LSD) test at the 95% level.
Results and Discussion
Increasing the amount of gas during the bubbling process improved the flow rate. Also, the results showed that the decreasing trend of the permeate flux at the gassing rate of 1.5 L/min was less than other treatments and more stable conditions were seen in the sap flux during the process. Also, the amount of flux in the interrupted form of bubbling showed that after the application of bubbling, although the amount of flux increased, but after that, during the ultra-refining process, the flux decreased again and did not remain constant at that level. But in general, despite the fact that the average flux was higher in the continuous process compared to the interrupted state, there was no significant difference between them. The results related to the amount of membrane fouling after applying the process showed that by applying bubble generation in both continuous and interrupted mods, the fouling was significantly reduced compared to the usual state of ultrafiltration. Also, as the amount of gas entering the feed stream increased, the membrane fouling decreased, which was slightly higher in the continuous state than in the interrupted mod. The overall hydrodynamic resistance of the membrane in different filtration modes showed that the difference between the overall resistance of the membrane in the ultrafiltration and the ultrafiltration process with gasification is quite significant. However, although the overall resistance of the membrane in the interrupted gassing state is higher than its continuous state due to more clogging, there is no significant difference between them (P<0.05).Since the flux changes and the amount of gel layer formation affect the properties of the purified syrup, the properties of the syrup were also investigated in the best flux created in two continuous and interrupted modes. The results showed that the continuous flow of gasification caused a small defect in the purification properties such as purity, color and turbidity due to the improvement of the permeate flow flux, which of course can be ignored in the sugar industry due to the improvement of the permeate flow flux.
Conclusion
Therefore, in general, it can be said that the discontinuous method, due to less gas consumption during bubbling and no significant difference in the amount of flux compared to the continuous mode, can be considered as the optimal mode of gasification during the experiments conducted in this research be placed.
Research Interests:
Introduction Celiac disease is one of the most common digestive disorder. Chicken nugget is one of the most popular instant and ready-to-eat foods, and wheat flour is one of its main coating ingredients, which contains approximately 60%... more
Introduction
Celiac disease is one of the most common digestive disorder. Chicken nugget is one of the most popular instant and ready-to-eat foods, and wheat flour is one of its main coating ingredients, which contains approximately 60% gluten. Quinoa is a gluten-free grain, as a good source of dietary fiber, has various applications in the meat products processing system as a stabilizer, fat substitute, structural components, etc. The addition of hydrocolloids also helps to improve the rheological properties of gluten-free products. The purpose of this research was to evaluate the effect of quinoa-corn mixed flour in the preparation of nugget batter as a gluten-free combination as an alternative to wheat flour, and also to investigate the effect of adding HPMC hydrocolloid on the final product characteristics. In this research, a rotatable central composite design was used to investigate the effect of two independent variables including different proportions of quinoa-corn flour (0-100, 50-50, 100-0%) and different levels of hydrocolloid (0.5-1-1.5%) on the quality characteristics of nugget. With the increase of quinoa replacement level, moisture content (0.60), batter pick up (138) and redness level 5.5 (a*) increased, and oil content (11), hardness (7.5), brightness level 41(L*), yellowness level 20(b*) decreased. The increase of HPMC also caused an increase in moisture content (0.59), brightness level (L*) of 0.39, batter pick up (137) and decrease in oil content (10) and hardness (7). Optimum conditions for the production of gluten-free nugget were determined by considering the optimal amounts for the production of high quality and healthy products, contained 90% quinoa and HPMC at a level of about 1%.
Materials and Methods
Corn flour was purchased from the pilot of Ferdowsi University of Mashhad. The de-saponified quinoa was prepared from Kashmir and then ground. In order to make the grains more uniform, both flours were sieved using a 30 mesh. Hydrocolloid hydroxypropyl methylcellulose was also prepared from Kian Shimi Mashhad. Oyla frying oil was used for frying the samples.
The chicken nugget formulation was a mixture of 86% minced chicken, 10% onion, 1.5% garlic powder, 1% salt and 1.5% pepper. After complete mixing, these materials were poured into a freezer bag until a homogeneous and uniform mixture was obtained, and they were flatted until they reached the desired thickness (1 cm). Plastics containing chicken paste were stored in the freezer for 2 hours to facilitate cutting. Then molding was done with a circular mold with a diameter of 4 cm (Dehghan Nasiri et al., 2012).The batter formulation consisted of flour, water, baking powder, salt and hydrocolloids. In order to investigate the effect of quinoa and corn flours, and hydrocolloids, these substances were added to nugget water paste in different percentages (quinoa-corn ratio: 0-100, 50-50, 0-100 and hydrocolloids at the level of 1-1 / 5 -0.5%) and then mixed with water by mixer for 1 minute. The molded samples were first coated with flour and then immersed in the batter for 60 seconds and dripped for 30 seconds. Finally, deep frying was performed in the fryer at 170 ° C for 3.5 minutes. The fried samples were taken out of the fryer basket and the excess oil on the surface of the nuggets was removed with absorbent paper. The oil was changed after twice frying. After cooling the samples at room temperature, the tests such as moisture content, oil content, texture (hardness), color, batter pick up, peroxide and overall acceptance were performed.
In this study, Design Expert 10.0.7 software and a rotatable central composite design to investigate the effect of two independent variables including different ratios of quinoa-corn flour (0-100, 50-50, 0-100%) and hydrocolloid (0.5-1-1.5%), Was used on the quality characteristics of the nugget. Finally, different models were fitted to the data obtained from the experiments and the best model was selected according to the results of analysis of variance.
Results and Discussion
With increasing quinoa replacement level, moisture content, redness (a*) and pH increased and oil content, batter pick up, texture (hardness), brightness (L*), yellowness (b*) and cooking loss decreased. Increasing the HPMC also increased the moisture content, brightness (L*), cooking loss, batter pick up, and decreased oil content and hardness. Optimum condition for production of gluten-free chicken nuggets, considering the appropriate properties was found to be 90% quinoa flour and 1% HPMC.
Conclusion
In general, it can be concluded that the addition of quinoa and HPMC leads to the production of high quality products with high moisture and low oil content and high nutritional value.
Celiac disease is one of the most common digestive disorder. Chicken nugget is one of the most popular instant and ready-to-eat foods, and wheat flour is one of its main coating ingredients, which contains approximately 60% gluten. Quinoa is a gluten-free grain, as a good source of dietary fiber, has various applications in the meat products processing system as a stabilizer, fat substitute, structural components, etc. The addition of hydrocolloids also helps to improve the rheological properties of gluten-free products. The purpose of this research was to evaluate the effect of quinoa-corn mixed flour in the preparation of nugget batter as a gluten-free combination as an alternative to wheat flour, and also to investigate the effect of adding HPMC hydrocolloid on the final product characteristics. In this research, a rotatable central composite design was used to investigate the effect of two independent variables including different proportions of quinoa-corn flour (0-100, 50-50, 100-0%) and different levels of hydrocolloid (0.5-1-1.5%) on the quality characteristics of nugget. With the increase of quinoa replacement level, moisture content (0.60), batter pick up (138) and redness level 5.5 (a*) increased, and oil content (11), hardness (7.5), brightness level 41(L*), yellowness level 20(b*) decreased. The increase of HPMC also caused an increase in moisture content (0.59), brightness level (L*) of 0.39, batter pick up (137) and decrease in oil content (10) and hardness (7). Optimum conditions for the production of gluten-free nugget were determined by considering the optimal amounts for the production of high quality and healthy products, contained 90% quinoa and HPMC at a level of about 1%.
Materials and Methods
Corn flour was purchased from the pilot of Ferdowsi University of Mashhad. The de-saponified quinoa was prepared from Kashmir and then ground. In order to make the grains more uniform, both flours were sieved using a 30 mesh. Hydrocolloid hydroxypropyl methylcellulose was also prepared from Kian Shimi Mashhad. Oyla frying oil was used for frying the samples.
The chicken nugget formulation was a mixture of 86% minced chicken, 10% onion, 1.5% garlic powder, 1% salt and 1.5% pepper. After complete mixing, these materials were poured into a freezer bag until a homogeneous and uniform mixture was obtained, and they were flatted until they reached the desired thickness (1 cm). Plastics containing chicken paste were stored in the freezer for 2 hours to facilitate cutting. Then molding was done with a circular mold with a diameter of 4 cm (Dehghan Nasiri et al., 2012).The batter formulation consisted of flour, water, baking powder, salt and hydrocolloids. In order to investigate the effect of quinoa and corn flours, and hydrocolloids, these substances were added to nugget water paste in different percentages (quinoa-corn ratio: 0-100, 50-50, 0-100 and hydrocolloids at the level of 1-1 / 5 -0.5%) and then mixed with water by mixer for 1 minute. The molded samples were first coated with flour and then immersed in the batter for 60 seconds and dripped for 30 seconds. Finally, deep frying was performed in the fryer at 170 ° C for 3.5 minutes. The fried samples were taken out of the fryer basket and the excess oil on the surface of the nuggets was removed with absorbent paper. The oil was changed after twice frying. After cooling the samples at room temperature, the tests such as moisture content, oil content, texture (hardness), color, batter pick up, peroxide and overall acceptance were performed.
In this study, Design Expert 10.0.7 software and a rotatable central composite design to investigate the effect of two independent variables including different ratios of quinoa-corn flour (0-100, 50-50, 0-100%) and hydrocolloid (0.5-1-1.5%), Was used on the quality characteristics of the nugget. Finally, different models were fitted to the data obtained from the experiments and the best model was selected according to the results of analysis of variance.
Results and Discussion
With increasing quinoa replacement level, moisture content, redness (a*) and pH increased and oil content, batter pick up, texture (hardness), brightness (L*), yellowness (b*) and cooking loss decreased. Increasing the HPMC also increased the moisture content, brightness (L*), cooking loss, batter pick up, and decreased oil content and hardness. Optimum condition for production of gluten-free chicken nuggets, considering the appropriate properties was found to be 90% quinoa flour and 1% HPMC.
Conclusion
In general, it can be concluded that the addition of quinoa and HPMC leads to the production of high quality products with high moisture and low oil content and high nutritional value.
Research Interests:
Introduction The use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious... more
Introduction
The use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious problems in their utilization. Excessive use of synthetic preservatives, which some of them are suspected to be toxic, has completely eliminated these additives and led to the use of natural alternatives to preserve or extend the shelf life of food products. Many plant-based bioactive compounds are good alternatives to synthetic antimicrobial and antioxidant supplements. Plant extracts have significant biological activity including antioxidant, antibacterial, and antifungal properties, which has increased their use in food products. In addition, plant-derived antimicrobial compounds have been considered in the pharmaceutical industry to control microbial pathogens. Natural antioxidant and antimicrobial compounds are receiving a lot of research and industrial attention in food preservation technologies. In the last 2 decades, the use of herbal medicines rich in bioactive molecules (including polyphenols, carotenoids and flavonoids) with medicinal and health effects such as delaying the onset of some diseases such as cardiovascular disorders, diabetes, and cancer have increased.
The plant Prosopis farcta grown in arid and semi-arid regions. In Iran, it is found in the southern regions of the country. In traditional medicine, this plant is used to prevent hyperlipidemia and hyperglycemia, to treat hemorrhoids, intestinal diseases and diarrhea, and leprosy, and to reduce abortion. In addition, antimicrobial and antioxidant properties of various species of Prosopis have been reported. Accordingly, in this study, after examining the of total phenols and flavonoids concentrations, the antioxidant and antimicrobial properties of ethanolic extract of Prosopis farcta were determined.
Materials and Methods
The ethanolic extract of P. farcta was obtained maceration method. Total phenol content (by Folin-Ciocalteu reagent method), total flavonoid content (by aluminum chloride method), antioxidant activity (by DPPH and ABTS free radical scavenging and beta-carotene bleaching methods), and antimicrobial effect against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated.
Results and Discussion
P. farcta ethanolic extract showed high phenol content (145.58 ± 1.30 mg GAE/g), while its total flavonoid content was 72.37 ± 1.48 mg QE/g. Antioxidant activity of ethanolic extract of melon root using different methods of DPPH and ABTS free radical scavenging and beta-carotene bleaching inhibition were 62.60, 71.82 and 54.50%, respectively. Antibacterial activity of P. farcta ethanolic extract against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis according to disk diffusion agar and well diffusion agar methods showed that the antimicrobial activity of the extract was concentration dependent and Shigella dysentery and Staphylococcus aureus were the most resistant and sensitive bacterial strains to the extract respectively. The minimum inhibitory concentrations of ethanolic extract of P. farcta root for Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis were 8, 8, 4 and 4 mg/ml, respectively; while the minimum bactericidal concentrations for these bacteria were 128, 256, 32 and 64 mg/ml, respectively.
Conclusion
In the present study, ethanolic extract obtained from the roots of P. farcta was identified as a rich source of phenolic and flavonoid compounds. The ethanolic extract showed effective antimicrobial and antioxidant properties. The results greatly indicated the promising effect of P. farcta root extract against Gram-positive and Gram-negative bacterial species. As the microbial resistance is constantly increasing, ethanolic extract of P. farcta root can be considered as a suitable complementary option to tackle this problem. In addition, the identification of individual components of P. farcta ethanolic extract and their biological functions or their combination with common antioxidant and antimicrobial agents could be the subject of future research.
The use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious problems in their utilization. Excessive use of synthetic preservatives, which some of them are suspected to be toxic, has completely eliminated these additives and led to the use of natural alternatives to preserve or extend the shelf life of food products. Many plant-based bioactive compounds are good alternatives to synthetic antimicrobial and antioxidant supplements. Plant extracts have significant biological activity including antioxidant, antibacterial, and antifungal properties, which has increased their use in food products. In addition, plant-derived antimicrobial compounds have been considered in the pharmaceutical industry to control microbial pathogens. Natural antioxidant and antimicrobial compounds are receiving a lot of research and industrial attention in food preservation technologies. In the last 2 decades, the use of herbal medicines rich in bioactive molecules (including polyphenols, carotenoids and flavonoids) with medicinal and health effects such as delaying the onset of some diseases such as cardiovascular disorders, diabetes, and cancer have increased.
The plant Prosopis farcta grown in arid and semi-arid regions. In Iran, it is found in the southern regions of the country. In traditional medicine, this plant is used to prevent hyperlipidemia and hyperglycemia, to treat hemorrhoids, intestinal diseases and diarrhea, and leprosy, and to reduce abortion. In addition, antimicrobial and antioxidant properties of various species of Prosopis have been reported. Accordingly, in this study, after examining the of total phenols and flavonoids concentrations, the antioxidant and antimicrobial properties of ethanolic extract of Prosopis farcta were determined.
Materials and Methods
The ethanolic extract of P. farcta was obtained maceration method. Total phenol content (by Folin-Ciocalteu reagent method), total flavonoid content (by aluminum chloride method), antioxidant activity (by DPPH and ABTS free radical scavenging and beta-carotene bleaching methods), and antimicrobial effect against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated.
Results and Discussion
P. farcta ethanolic extract showed high phenol content (145.58 ± 1.30 mg GAE/g), while its total flavonoid content was 72.37 ± 1.48 mg QE/g. Antioxidant activity of ethanolic extract of melon root using different methods of DPPH and ABTS free radical scavenging and beta-carotene bleaching inhibition were 62.60, 71.82 and 54.50%, respectively. Antibacterial activity of P. farcta ethanolic extract against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis according to disk diffusion agar and well diffusion agar methods showed that the antimicrobial activity of the extract was concentration dependent and Shigella dysentery and Staphylococcus aureus were the most resistant and sensitive bacterial strains to the extract respectively. The minimum inhibitory concentrations of ethanolic extract of P. farcta root for Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis were 8, 8, 4 and 4 mg/ml, respectively; while the minimum bactericidal concentrations for these bacteria were 128, 256, 32 and 64 mg/ml, respectively.
Conclusion
In the present study, ethanolic extract obtained from the roots of P. farcta was identified as a rich source of phenolic and flavonoid compounds. The ethanolic extract showed effective antimicrobial and antioxidant properties. The results greatly indicated the promising effect of P. farcta root extract against Gram-positive and Gram-negative bacterial species. As the microbial resistance is constantly increasing, ethanolic extract of P. farcta root can be considered as a suitable complementary option to tackle this problem. In addition, the identification of individual components of P. farcta ethanolic extract and their biological functions or their combination with common antioxidant and antimicrobial agents could be the subject of future research.
Research Interests:
Introduction Doogh is a fermented dairy product that is produced by blending yogurt with water and some salt. This fermented beverage is widely consumed as a refreshing drink in Iran and other Middle East countries. Doogh is a source of... more
Introduction
Doogh is a fermented dairy product that is produced by blending yogurt with water and some salt. This fermented beverage is widely consumed as a refreshing drink in Iran and other Middle East countries. Doogh is a source of calcium needed by the body on a daily basis and contains B vitamins that are effective in the health and strength of teeth and bones. In addition, doogh contains a low percentage of fat, which makes it a diet drink. Whey Protein Concentrate (WPC) is a product contains 25 to 89% protein and different amounts of lactose, fat and minerals. Due to the functional properties of whey protein and its nutritional value; whey protein is widely used in dairy products. The development of cross-linking bonds between protein chains by enzymes is very important today. Enzyme cross-linking of proteins can affect some of their functional properties such as solubility, water absorption, rheological and emulsifying properties. One of the most widely used enzymes in the food industry is the transglutaminase enzyme. In this study the effects of WPC in three levels (0%,1% and 2%) and the transglutaminase enzyme in two levels (0 and 1 unit per gram of milk protein) in two method of dough preparation (adding water to yogurt and fermented milk diluted with water) on rheological characteristics, and microstructure of doogh were studied.
Material and Methods
Raw milk was provided by Pegah Khorasan Company, WPC from Multi Company) Mashhad (and Trans glutaminease enzyme from BDF Company of Spain. WPC was first added to milk at 45 ̊ C at three levels of zero, 1 and 2%.The milk samples were then pasteurized at 85 ̊ C for 30 min. After lowering the temperature to 45 ̊ C, the enzymatic operation was performed at two levels of zero and one unit (per gram of protein).To complete the enzyme function, the samples were incubated for 180 minutes at 45 ̊ C. Then a temperature of 90 ̊ C was applied for 1 minute to inactivate the enzyme. The samples were then cooled to 45 ̊ C. At this stage, the samples were divided into two parts. In one part of the samples; milk was diluted with water in a ratio of 6% of the total dry matter for direct production of doogh. After adding the starter, the samples were transferred to an incubator and hold at 43-42 ̊ C, until the pH reaches about 4.1.Thefermented samples were then transferred to a refrigerator. In the second part, starter was added to milk to produce yogurt; after adding starter, the mix was transferred to an incubator and hold at 43-42 ̊ C, until the pH reaches about 4.1. Doogh was produced by diluting yogurt with waterto givethe final product with 6% of total dry matter.
Results and Discussion
In both production methods, in samples treated only with WPC, the average particle size increased with increasing WPClevel. In both methods, the production of only enzymatically treated samples led to the formation of smaller particles with a more uniform shape and distribution. In samples of doogh produced by both production methods, WPC and transglutaminase enzyme changed the flow characteristics of doogh to non-Newtonian behavior. Samples made directly from milk had significantly higher viscosity than samples made from yogurt. In samples without enzymatic treatment, the microstructure was smooth and homogeneous with smaller particles than other samples. These particles settle very quickly. In the samples where WPC treatment was applied, the amount of large particles and non-uniformity increase with increasing WPC level. The distribution of particles in samples made directly from milk was more regular than samples made from yogurt.
Doogh is a fermented dairy product that is produced by blending yogurt with water and some salt. This fermented beverage is widely consumed as a refreshing drink in Iran and other Middle East countries. Doogh is a source of calcium needed by the body on a daily basis and contains B vitamins that are effective in the health and strength of teeth and bones. In addition, doogh contains a low percentage of fat, which makes it a diet drink. Whey Protein Concentrate (WPC) is a product contains 25 to 89% protein and different amounts of lactose, fat and minerals. Due to the functional properties of whey protein and its nutritional value; whey protein is widely used in dairy products. The development of cross-linking bonds between protein chains by enzymes is very important today. Enzyme cross-linking of proteins can affect some of their functional properties such as solubility, water absorption, rheological and emulsifying properties. One of the most widely used enzymes in the food industry is the transglutaminase enzyme. In this study the effects of WPC in three levels (0%,1% and 2%) and the transglutaminase enzyme in two levels (0 and 1 unit per gram of milk protein) in two method of dough preparation (adding water to yogurt and fermented milk diluted with water) on rheological characteristics, and microstructure of doogh were studied.
Material and Methods
Raw milk was provided by Pegah Khorasan Company, WPC from Multi Company) Mashhad (and Trans glutaminease enzyme from BDF Company of Spain. WPC was first added to milk at 45 ̊ C at three levels of zero, 1 and 2%.The milk samples were then pasteurized at 85 ̊ C for 30 min. After lowering the temperature to 45 ̊ C, the enzymatic operation was performed at two levels of zero and one unit (per gram of protein).To complete the enzyme function, the samples were incubated for 180 minutes at 45 ̊ C. Then a temperature of 90 ̊ C was applied for 1 minute to inactivate the enzyme. The samples were then cooled to 45 ̊ C. At this stage, the samples were divided into two parts. In one part of the samples; milk was diluted with water in a ratio of 6% of the total dry matter for direct production of doogh. After adding the starter, the samples were transferred to an incubator and hold at 43-42 ̊ C, until the pH reaches about 4.1.Thefermented samples were then transferred to a refrigerator. In the second part, starter was added to milk to produce yogurt; after adding starter, the mix was transferred to an incubator and hold at 43-42 ̊ C, until the pH reaches about 4.1. Doogh was produced by diluting yogurt with waterto givethe final product with 6% of total dry matter.
Results and Discussion
In both production methods, in samples treated only with WPC, the average particle size increased with increasing WPClevel. In both methods, the production of only enzymatically treated samples led to the formation of smaller particles with a more uniform shape and distribution. In samples of doogh produced by both production methods, WPC and transglutaminase enzyme changed the flow characteristics of doogh to non-Newtonian behavior. Samples made directly from milk had significantly higher viscosity than samples made from yogurt. In samples without enzymatic treatment, the microstructure was smooth and homogeneous with smaller particles than other samples. These particles settle very quickly. In the samples where WPC treatment was applied, the amount of large particles and non-uniformity increase with increasing WPC level. The distribution of particles in samples made directly from milk was more regular than samples made from yogurt.
Research Interests:
Introduction Cucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage... more
Introduction
Cucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.
Materials and Methods
The inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used.
Results and Discussion
The results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced.
Conclusion
The results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
Cucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.
Materials and Methods
The inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used.
Results and Discussion
The results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced.
Conclusion
The results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
Research Interests:
Preparing air-in-oil-in-water (A/O/W) double emulsion involves two key steps: oleofoam formation and dispersion of the oleofoam in an aqueous solution containing protein as an emulsifier and hydrocolloid as a thickening agent. This study... more
Preparing air-in-oil-in-water (A/O/W) double emulsion involves two key steps: oleofoam formation and dispersion of the oleofoam in an aqueous solution containing protein as an emulsifier and hydrocolloid as a thickening agent. This study aimed to investigate the effect of oleofoam level and varying concentrations of protein-polysaccharide ratios on the thermal stability, encapsulation yield and rheological properties of A/O/W double emulsion. An oleofoam was obtained using a lipophilic emulsifier (distilled monoglyceride MG) and sunflower oil at 5°C with maximum stability. Two levels of oleofoam (20% and 25 wt %) were added to an aqueous solution containing different concentrations of sodium caseinate (SC) (5, 8, and 10 wt %) and kappa carrageenan (KC) (0.4 and 0.8 wt %). Results indicate that oleofoam level did not significantly affect air encapsulation efficiency and particle size, while protein-polysaccharide ratios could significantly impact all properties of A/O/W double emulsion. Increasing the concentration of sodium caseinate and kappa carrageenan improved thermal stability and encapsulation yield while simultaneously reducing particle size. All A/O/W emulsions exhibited shear thinning behavior among the range of shear rates studied, indicating significant potential for food applications.
Research Interests:
In recent years, the use of propolis in food products has received attention owing to its functional role. This study was conducted to investigate the effect of different concentrations of propolis extract on the total polyphenol content... more
In recent years, the use of propolis in food products has received attention owing to its functional role. This study was conducted to investigate the effect of different concentrations of propolis extract on the total polyphenol content and antioxidant activity of raw milk. For this purpose, an aqueous extract of dry propolis was prepared and stored in dark-colored bottles at 4 °C until the day of experiments. The propolis extract was added to raw milk in concentrations of 0, 4.7, 9.1, 16.6, and 28.5%. Total phenolic content and antioxidant activity were measured using the colorimetric Folin-Ciocalteu method and DPPH assay, respectively. Measurements were performed on the first day at zero hour and after 6 and 24 h of treatment, and the storage temperature was maintained at 5°C until analyzed. The amount of total polyphenol increased with the increase in the concentration of propolis extract in the treated milk in 0 hour; accordingly, the lowest and the highest amounts of total polyphenol were related to control milk and milk containing 28.5% propolis extract, respectively. A decreasing trend was observed in total polyphenol in the control sample and raw milk containing 4.7% propolis extract during 24 hours. There was an increase in total polyphenol content in raw milk containing 9.1% and 16.6% propolis extracts, the trend of changes in raw milk containing 28.5% extract was insignificant. The addition of propolis extract caused an increase in the antioxidant activity and total phenolic content in raw milk. According to the results, it is recommended to carry out more studies to clarify the functions of propolis's total polyphenol content and its interaction with milk proteins.
Research Interests:
The increasing growth of cardiovascular diseases, high blood pressure, and hardening of the vessel walls as well as obesity in many countries has made low-fat and low sodium pizza cheese one of the subjects of study all over the world.... more
The increasing growth of cardiovascular diseases, high blood pressure, and hardening of the vessel walls as well as obesity in many countries has made low-fat and low sodium pizza cheese one of the subjects of study all over the world. The effects of four important independent variables including inulin (0-0.025 %), pre-gelatinized starch (0-0.5 %), NaCl (0.35-1%), and KCl (0.35-1%) were studied. The fat content of imitation pizza cheese was significantly decreased to 11.91% with the increased levels of inulin and starch substitution (p<0.05). Also, its moisture and pH values were significantly different (p < 0.05). The increased levels of pre-gelatinized starch and inulin reduced hardness (from 5.04 to 3.55) and adhesiveness (from 4368.89% to 1640.54%), however, increased cohesiveness (from 0.365 to 0.43) and springiness (from 0.456 to 0.545). NaCl and KCl increased the hardness of the product. Inulin and starch led to decrease the a* value. The b* value decreases with the increase of inulin and increases with the increase of modified starch. The formulation containing 0.19% inulin, 0.4% pre-gelatinized starch, 0.35% NaCl, and 0.50% KCl was found as the optimal formulation for low-fat imitation cheese. Results of scanning electron microscope (SEM) images revealed that inulin crystals were accumulated in the continuous phase, which this can lead to important changes in the sensory and textural properties. The study concludes that inulin or starch can be used to replace up to 3.6% of fat in the imitation pizza cheese and 0.35% NaCl-0.50% KCl to lower the sodium content of the product.
Research Interests:
Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them... more
Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them potentially high-risk fresh products. This study aimed to assess the effect of emulsion coating consisting of Dracocephalum kotschyi essential oil (0, 50, 150, 250, 300 ppm)-chitosan solution (0, 0.3, 0.38, 0.63, 0.75%) during the immersion time (10, 25, 55, 85, 100 s) on the microbial properties of fresh sprouted wheat stored at 4°C. The Response Surface Methodology (RSM) was adopted in modeling the independent variables’ effects. The results shown that increase in the essential oil and chitosan solution concentration reduced the microbial spoilage. High concentration of Dracocephalum kotschyi oil decreased the fungus population after 12 days. Coating of sprouted wheat at optimized level of independent variables (0.62% chitosan, 57 ppm Dracocephalum kotschyi oil and 29.49 s immersion time) reduced the microbial and fungal populations. This treatment can reduce weight loss, and maintain tissue firmness, total phenolic, and ascorbic acid content of the sprouted wheat during cold storage, with no effect on its sensory properties. Our findings indicate that nanoemulsion coating based on chitosan and Dracocephalum kotschyi oil at appropriate levels could be beneficial in maintaining sprouted wheat quality and increasing its shelf-life.
Research Interests:
The present investigation was done to study the effects of Lactococcus lactis (L. lactis) subsp. lactis on the shelf life of the vacuum-packaged Oncorhynchus mykiss. Fish fillets were prepared and divided into 5 different treatment groups... more
The present investigation was done to study the effects of Lactococcus lactis (L. lactis) subsp. lactis on the shelf life of the vacuum-packaged Oncorhynchus mykiss. Fish fillets were prepared and divided into 5 different treatment groups including control (distilled water), 2% and 4% supernatant, and 106 CFU/g L. lactis subspecies lactis. The pH, Thiobarbituric Acid Reactive Substances (TBARS), Total volatile Nitrogen (TVN), and Peroxide Value (PV) of the fillets were determined on days 0, 5, 10, and 15 while maintained at 4˚C. Protein expression and destruction were analyzed using the SDS-PAGE. The organoleptic assessment was done using five expert sensory panelists. Contents of TBARS, TVN, pH, and PV were increased throughout the storage period (P <0.05). An increase in the concentration of supernatant caused a significant decrease in the content of TBARS, TVN, pH, and PV (P <0.05). The highest and lowest contents of TBARS, TVN, pH and PV on 15th day were belonged to the control (3.367±0.04 mg MDA/kg) and pure bacteria (0.70±0.02 mg MDA/kg), control (87.20±6.40 mg/100g) and 4% supernatant (40.79±0.61 mg/100g), pure bacteria (6.23±0.04) and 4% supernatant (5.44±0.07) and control (12.22±0.01 meq/kg) and 4% supernatant (3.08±0.06 meq/kg) groups, respectively. Protein destruction was lower in the fillet samples treated with pure bacteria and 4% supernatant. The highest scores of the odor, flavor, texture, and color were obtained for fillets treated with 4% supernatant, pure bacteria, pure bacteria, and 4% supernatant and pure bacteria, respectively. The results revealed that treating O. mykiss fillets with 4% supernatant and 106 CFU/g of pure L. lactis subsp. lactis can extend the shelf life of O. mykiss fillets.
Research Interests:
Over the past decades, the use of natural additives has increased as an alternative to artificial ingredients in the food industry. The purpose of this study was to investigate the potential of pomegranate peel (PP) as a natural food... more
Over the past decades, the use of natural additives has increased as an alternative to artificial ingredients in the food industry. The purpose of this study was to investigate the potential of pomegranate peel (PP) as a natural food additive. Many factors, including genotype, could affect the quality of PP as a by-product of juice production with many nutritional, functional and anti-infective properties. In this study, the most significant phytochemical characters of thirty Iranian pomegranate peels (IPP) from different genotypes, including total phenolic (TPC) and flavonoid content (TFC), and nine phenolic compounds were determined. The HPLC-DAD-MS results of PPEs revealed nine phenolic compounds in the IPP extracts. Punicalagin β, punicalagin α, and ellagic acid were the main components constituting 20.8–48.7, 13.9–30.1, and 1.6–13.4 μg/mg DW, respectively. The peel of IPP23 (Kabdar-Shirin-e- Behshahr) contained the highest quantity of polyphenolic compounds. Also, TPC and TFC of the peel extracts ranged between 66.38 and 181.41 mg GAE/ g DW and 38.5 to 144.13 mg RE/ g DW, respectively. Eventually, antioxidant potential estimated by the DPPH assay ranged between 4.1 and 14.4 μg/ml. The results showed that the antioxidant property of pomegranate peel extracts is significantly higher than the standard of gallic acid. Also, the peel of the genotypes that had high phenolic compounds were introduced as superior genotypes. The results of HCA showed that, among the studied genotypes, the peel of IPP23 can be introduced as a potential source of natural preservatives in the food industry.
Research Interests:
Introduction Tomato paste is one of the processed tomato products that has a long shelf life and is used as an important food ingredient all over the world. According to global statistics, Iran is among the top ten producers of tomato... more
Introduction
Tomato paste is one of the processed tomato products that has a long shelf life and is used as an important food ingredient all over the world. According to global statistics, Iran is among the top ten producers of tomato paste in the world, Iran ranks fourth to fifth in the world in the field of aseptic paste production. Alicyclobacillus bacteria are considered as a risk for pasteurized acidic food industries. These bacteria enter the product through soil-contaminated fruits, production equipment of the factories and finally produce metabolites such as guaiacol, causing an unpleasant taste in the product.
Materials and Methods
In order to investigate the microbial contamination of canned tomato paste in the country, 46 samples of canned tomato paste in the amount of 184 cans of 800 grams were purchased from the market. Regarding the purchase of samples from the market, we tried to buy a different production date and production series for each sample (approximately 4 cans for each brand from each production series). The purchased samples were sent to the Microbiology Department of the Standard Research Institute laboratory for microbiology tests. At the same time, the culture media of thermophilic bacteria (Orange Serum Agar, Thermoacidurans Agar from 4 available brands) were tested for performance control. The canned tomato paste samples were incubated at 30°C ± 1°C for 14 days and 55°C ± 1°C for 7 days.
Results and Discussion
The contents of both examined samples were tested separately for thermophilic bacteria, mesophilic bacteria, mold and yeast. Out of the 46 samples prepared with different production dates and production series, which were 46 cans of tomato paste, 28 samples were positive in terms of contamination with thermophilic bacteria. According to the number of contaminated samples, it was found that 60.86% of the samples were contaminated. Colonies grown on Thermoacidurans Agar medium were examined morphologically. For further investigations, gram staining was performed. All the stained colonies morphologically showed the form of gram-positive rod-shaped bacilli. Biochemical tests including catalase and oxidase were performed to identify Alicyclobacillus species. All the grown colonies were catalase positive and oxidase negative. The final identification of the species was done by performing molecular tests based on specific primers designed from Alicyclobacillus gene. These tests were performed in three stages: genomic DNA extraction, polymerase chain reaction and electrophoresis. Using the PCR method, the grown colonies were analyzed for two types of bacteria, Alicyclobacillus acidocaldarius and Bacillus coagulans. According to the results obtained from sequencing with designed primers in the NCBI database, it showed 100% similarity with the registered sequences, which are all different strains of the Alicyclobacillus acidocaldarius species. None of the colonies were detected as Bacillus coagulans species. Since Alicyclobacillus acidocaldarius was isolated from soil for the first time, the presence of these bacteria in the product indicates the contamination of raw materials with soil.
Conclusion
In this research, the presence of Alicyclobacillus bacteria in canned tomato paste was confirmed. Due to the high heat resistance of this bacteria, there is a possibility of the presence of Alicyclobacillus in the all stages of tomato paste production, which have entered the product through the soil, and 95°C ± 3°C pasteurization temperature in 30 minutes is not effective in removing this bacteria completely. Most acidophilus thermophilic bacteria, such as Alicyclobacillus family, are not pathogenic bacteria. Their presence in food may make the food taste bad or smelly, but it does not pose a risk to the health of the consumer. Therefore, in order to reduce the risk of spoilage and to prevent the growth of bacterial spores in the product, it is essential not to expose the product to high temperatures for a long time. It is also necessary to perform rapid cooling after heat treatment and keep the product at a temperature below 30°C.
Acknowledgement
This article is the result of a common research project of Microbiology and Biology Research Group of Standard Research Institute and Kermanshah Standard Regional Research Group. We hereby thank and appreciate the cooperation of the microbiology research group of the Standard Research Institute and the Kermanshah General Directorate of Standards. We are also very grateful to Rogin Talk Company as the employer of this project.
Tomato paste is one of the processed tomato products that has a long shelf life and is used as an important food ingredient all over the world. According to global statistics, Iran is among the top ten producers of tomato paste in the world, Iran ranks fourth to fifth in the world in the field of aseptic paste production. Alicyclobacillus bacteria are considered as a risk for pasteurized acidic food industries. These bacteria enter the product through soil-contaminated fruits, production equipment of the factories and finally produce metabolites such as guaiacol, causing an unpleasant taste in the product.
Materials and Methods
In order to investigate the microbial contamination of canned tomato paste in the country, 46 samples of canned tomato paste in the amount of 184 cans of 800 grams were purchased from the market. Regarding the purchase of samples from the market, we tried to buy a different production date and production series for each sample (approximately 4 cans for each brand from each production series). The purchased samples were sent to the Microbiology Department of the Standard Research Institute laboratory for microbiology tests. At the same time, the culture media of thermophilic bacteria (Orange Serum Agar, Thermoacidurans Agar from 4 available brands) were tested for performance control. The canned tomato paste samples were incubated at 30°C ± 1°C for 14 days and 55°C ± 1°C for 7 days.
Results and Discussion
The contents of both examined samples were tested separately for thermophilic bacteria, mesophilic bacteria, mold and yeast. Out of the 46 samples prepared with different production dates and production series, which were 46 cans of tomato paste, 28 samples were positive in terms of contamination with thermophilic bacteria. According to the number of contaminated samples, it was found that 60.86% of the samples were contaminated. Colonies grown on Thermoacidurans Agar medium were examined morphologically. For further investigations, gram staining was performed. All the stained colonies morphologically showed the form of gram-positive rod-shaped bacilli. Biochemical tests including catalase and oxidase were performed to identify Alicyclobacillus species. All the grown colonies were catalase positive and oxidase negative. The final identification of the species was done by performing molecular tests based on specific primers designed from Alicyclobacillus gene. These tests were performed in three stages: genomic DNA extraction, polymerase chain reaction and electrophoresis. Using the PCR method, the grown colonies were analyzed for two types of bacteria, Alicyclobacillus acidocaldarius and Bacillus coagulans. According to the results obtained from sequencing with designed primers in the NCBI database, it showed 100% similarity with the registered sequences, which are all different strains of the Alicyclobacillus acidocaldarius species. None of the colonies were detected as Bacillus coagulans species. Since Alicyclobacillus acidocaldarius was isolated from soil for the first time, the presence of these bacteria in the product indicates the contamination of raw materials with soil.
Conclusion
In this research, the presence of Alicyclobacillus bacteria in canned tomato paste was confirmed. Due to the high heat resistance of this bacteria, there is a possibility of the presence of Alicyclobacillus in the all stages of tomato paste production, which have entered the product through the soil, and 95°C ± 3°C pasteurization temperature in 30 minutes is not effective in removing this bacteria completely. Most acidophilus thermophilic bacteria, such as Alicyclobacillus family, are not pathogenic bacteria. Their presence in food may make the food taste bad or smelly, but it does not pose a risk to the health of the consumer. Therefore, in order to reduce the risk of spoilage and to prevent the growth of bacterial spores in the product, it is essential not to expose the product to high temperatures for a long time. It is also necessary to perform rapid cooling after heat treatment and keep the product at a temperature below 30°C.
Acknowledgement
This article is the result of a common research project of Microbiology and Biology Research Group of Standard Research Institute and Kermanshah Standard Regional Research Group. We hereby thank and appreciate the cooperation of the microbiology research group of the Standard Research Institute and the Kermanshah General Directorate of Standards. We are also very grateful to Rogin Talk Company as the employer of this project.
Research Interests:
Introduction As a useful fruit for humans, apple (Malus domestica) is a good sourceof antioxidants, minerals, ascorbic acid, vitamins, polyphenols, fibers and other essential elements with medicinal properties. Improving the storage time... more
Introduction
As a useful fruit for humans, apple (Malus domestica) is a good sourceof antioxidants, minerals, ascorbic acid, vitamins, polyphenols, fibers and other essential elements with medicinal properties. Improving the storage time of apple juice and maintaining the stability of extracts with high Brix value (during transportation and storage) and its marketability by removing the remaining water as well as reducing the turbidity, viscosity and brown color caused by colloidal suspended solids. Large (pectin, protopectin, pigments, polymeric carbohydrates, tannin, starch, cellulose, hemicellulose, fibers, etc.) is of great importance. Due to the presence of colloidal suspended solid particles and compounds that settle over time (mold, bacteria, plant cell fragments, pectin-tannin complex), apple juice must be clarified before concentration. Due to the high-energy consumption, time-consuming, degradation of thermo-sensitive components, and reduction of nutritional value in traditional methods, recently, the use of membrane concentration in food and beverage production holds great potential.. Despite all the benefits of membrane processes, one of the critical problems is permeate flux decline due to the concentration polarization and membrane fouling. In this study, an innovative mechanical motion was developed to remove the cake deposits on the membrane surface towards mitigating adverse effects of polarization and fouling.
Materials and Methods
Membrane scraped surface module was designed and made with polyethylene material. The membrane was enclosed between the lower and upper parts of the module. These two parts are connected with screws and create a cylindrical part. Also, two caps are pressed axially to this cylindrical part by a metal frame to eliminate any unwanted leakage. The rotor shaft was coupled with an electric motor and the rotation of the output shaft was regulated by an inverter. A pump transferred the fresh fruit juice to the module through the inlet port and then it was divided into two output streams, permeate and retentate. The permeate was collected from the bottom of the module for further investigation and the retentate was returned to the juice tank. A polyethersulfone (PES) membrane with molecular weight cut-off (MWCO) of 4 kDa was used to clarify apple juice. Effects of the blade rotation speed (0, 600, 1400 and 2200 rpm), transmembrane pressure (TMP) (0.5, 1 and 1.5 bar), feed flow rate (FFR) (10, 15 and 20 ml/s) and the distance of the blade from the membrane surface (2 and 5 mm) on volumetric concentration factor (VCF) and fouling phenomenon were evaluated. Hermia model was used to study the main fouling mechanism and it was verified by scanning electron microscopy (SEM) images.
Results and Discussion
Results showed that rotating the blade with speed of 600 rpm at TMP of 0.5 bar, FFR of 10 ml/s and 2 mm distance from the membrane surface had the best performance in VCF and reducing fouling. The main mechanism of fouling was cake formation. Rotation of the blade decreases the intensity of cake formation and its thickness on the membrane surface and enhances the standard pore blocking. Also increasing the blade rotation speed changes the main fouling mechanism to the standard pore blocking due to the cake disintegration on the membrane surface and the penetration of fine particles into the membrane pores. As a result, the rotation of blade had a significant positive effect on increasing the VCF. On the other hand, the total resistance decreased with the rotation of the blade and by increasing the distance of blade from the membrane surface, the intensity of cake formation reduced. Also, the SEM images showed that in without blade rotation mode, the accumulation of cake particles on the membrane surface is thicker and denser than in with blade rotation mode. On the other hand, the low thickness of the cake layer formed on the membrane surface in the process of blade rotation is due to the turbulences resulting from the rotating blade. These observations confirm the results of the Hermia model in the previous sections.
Conclusion
In conclusion, the TMP 0.5 bar, FFR of 10 ml/s, blade rotation speed of 600 rpm with a distance of 2 mm from membrane surface were considered as the best conditions for ultrafiltration of apple juice using scraped-surface membrane unit.
As a useful fruit for humans, apple (Malus domestica) is a good sourceof antioxidants, minerals, ascorbic acid, vitamins, polyphenols, fibers and other essential elements with medicinal properties. Improving the storage time of apple juice and maintaining the stability of extracts with high Brix value (during transportation and storage) and its marketability by removing the remaining water as well as reducing the turbidity, viscosity and brown color caused by colloidal suspended solids. Large (pectin, protopectin, pigments, polymeric carbohydrates, tannin, starch, cellulose, hemicellulose, fibers, etc.) is of great importance. Due to the presence of colloidal suspended solid particles and compounds that settle over time (mold, bacteria, plant cell fragments, pectin-tannin complex), apple juice must be clarified before concentration. Due to the high-energy consumption, time-consuming, degradation of thermo-sensitive components, and reduction of nutritional value in traditional methods, recently, the use of membrane concentration in food and beverage production holds great potential.. Despite all the benefits of membrane processes, one of the critical problems is permeate flux decline due to the concentration polarization and membrane fouling. In this study, an innovative mechanical motion was developed to remove the cake deposits on the membrane surface towards mitigating adverse effects of polarization and fouling.
Materials and Methods
Membrane scraped surface module was designed and made with polyethylene material. The membrane was enclosed between the lower and upper parts of the module. These two parts are connected with screws and create a cylindrical part. Also, two caps are pressed axially to this cylindrical part by a metal frame to eliminate any unwanted leakage. The rotor shaft was coupled with an electric motor and the rotation of the output shaft was regulated by an inverter. A pump transferred the fresh fruit juice to the module through the inlet port and then it was divided into two output streams, permeate and retentate. The permeate was collected from the bottom of the module for further investigation and the retentate was returned to the juice tank. A polyethersulfone (PES) membrane with molecular weight cut-off (MWCO) of 4 kDa was used to clarify apple juice. Effects of the blade rotation speed (0, 600, 1400 and 2200 rpm), transmembrane pressure (TMP) (0.5, 1 and 1.5 bar), feed flow rate (FFR) (10, 15 and 20 ml/s) and the distance of the blade from the membrane surface (2 and 5 mm) on volumetric concentration factor (VCF) and fouling phenomenon were evaluated. Hermia model was used to study the main fouling mechanism and it was verified by scanning electron microscopy (SEM) images.
Results and Discussion
Results showed that rotating the blade with speed of 600 rpm at TMP of 0.5 bar, FFR of 10 ml/s and 2 mm distance from the membrane surface had the best performance in VCF and reducing fouling. The main mechanism of fouling was cake formation. Rotation of the blade decreases the intensity of cake formation and its thickness on the membrane surface and enhances the standard pore blocking. Also increasing the blade rotation speed changes the main fouling mechanism to the standard pore blocking due to the cake disintegration on the membrane surface and the penetration of fine particles into the membrane pores. As a result, the rotation of blade had a significant positive effect on increasing the VCF. On the other hand, the total resistance decreased with the rotation of the blade and by increasing the distance of blade from the membrane surface, the intensity of cake formation reduced. Also, the SEM images showed that in without blade rotation mode, the accumulation of cake particles on the membrane surface is thicker and denser than in with blade rotation mode. On the other hand, the low thickness of the cake layer formed on the membrane surface in the process of blade rotation is due to the turbulences resulting from the rotating blade. These observations confirm the results of the Hermia model in the previous sections.
Conclusion
In conclusion, the TMP 0.5 bar, FFR of 10 ml/s, blade rotation speed of 600 rpm with a distance of 2 mm from membrane surface were considered as the best conditions for ultrafiltration of apple juice using scraped-surface membrane unit.
Research Interests:
Introduction Manufacturers are trying to replace plastic materials in the food packaging industry with biodegradable and edible films. Biodegradable edible films and coatings are mainly made from carbohydrates, lipids and proteins and... more
Introduction
Manufacturers are trying to replace plastic materials in the food packaging industry with biodegradable and edible films. Biodegradable edible films and coatings are mainly made from carbohydrates, lipids and proteins and their mixtures. In recent decades, various carbohydrates from plant sources have been investigated and introduced as new compounds for the preparation of these films. Flaxseed gum is a white to cream-colored powder that dissolves in water and produces a gel, and is a desirable compound for forming films and coatings. Recently, through the integration of reinforcements or fillers with at least one nanometer dimension in the substrate of one or more natural biopolymers, the physicochemical, mechanical, optical, thermal and barrier properties of pure biofilms have been improved. The use of cellulose nanoparticles in biofilms as a reinforcing agent for polymer materials leads to the creation of composite films with better quality characteristics and leads to the creation of functionalization activities in film production. Therefore, the aim of this research was to produce and characterize edible and biodegradable film based on the combination of flaxseed gum and cellulose nanocrystals.
Materials and Methods
Cellulose nanocrystals (Degree of crystallinity: 42% and average particle size: 58 nm) were extracted from cotton linters. Glycerol and other chemicals used for this research were obtained from Merck, Germany. Flaxseeds were purchased from the local market of Shiraz (Iran). Bionanocomposite films were prepared from different ratios (0:100, 30:70, 50:50, 70:30 and 100:0) of flaxseed mucilage (2% w/v) and cellulose nanocrystal (6% w/v) solutions. The prepared solutions were poured on a petri dish with a diameter of 15 cm and dried in an oven at 80°C for 4 hours. Their physical, color and mechanical properties were investigated and the best ratio was selected for the preparation of bionanocomposite film. The produced films were subjected to different analysis to determine thickness, solubility, water absorption capacity, permeability to water vapor, tensile strength, elongation at break point, and colorimetry. The microstructure of the produced film was studied using a scanning electron microscopy (SEM).The average data were analyzed by analysis of variance in a completely randomized design using SPSS 22.0 software. Differences between treatments were expressed in Duncan's multiple range test at the 95% probability level (p<0.05) and the corresponding graphs were drawn with Excel 2013.
Results and Discussion
The results of the film thickness test showed that the film containing 100% mucilage has the lowest thickness and with the addition of cellulose nanocrystals, the thickness increased significantly (p<0.05). The results of the water solubility and water absorption capacity of the film samples showed that the addition of cellulose nanocrystals to the flaxseed mucilage film initially led to a significant decrease in the water solubility and water absorption capacity (p<0.05), so that the lowest level ofthese two physical parameters were obtained in the film containing the combination of 70% flaxseed mucilage and 30% cellulose nanocrystal, and then with the increase of cellulose nanocrystals, an increase in water solubility and water absorption capacity of the films was observed. Nanocrystal cellulose at low levels (30%) acted as a filler and was uniformly dispersed in the network of the film and by filling the empty pores of the biopolymer film based on flaxseed mucilage, it caused the transfer of water vapor more complicated and reduced the permeability to water vapor. However, its higher amount increased the permeability of the film to water vapor.The results showed that by adding cellulose nanocrystal to the film based on flaxseed mucilage and increasing its amount, the brightness of the films decreased and the intensity of redness, yellowness and turbidity of the films increased significantly (p<0.05). By combining flaxseed mucilage and cellulose nanocrystals in a ratio of 30:70, the best film was produced in terms of mechanical strength and stability against moisture and water vapor. The SEM image of this film showed a smooth, even surface and a uniform distribution of cellulose nanocrystals in the film network.
Conclusion
The results finally showed that the combination of flaxseed mucilage and cellulose nanocrystals in a ratio of 30:70 was able to produce a biodegradable and edible film with favorable structural and barrier properties. The characteristics of this film include; thickness (0.313mm), solubility (53.42%), water absorption capacity (44.44%), permeability to water vapor (0.350 g.m-1s-1Pa-1 × 10 -10), tensile strength (0.973 MPa), elongation at break point (30.52%) were obtained. The colorimetric indices L*, a*, b* and turbidity were determined as 79.73, 1.95, 3.48 and 1.335 mm-1 respectively.
Acknowledgement
The authors would like to express their sincere gratitude to Islamic Azad University, Sarvestan Branch.
Manufacturers are trying to replace plastic materials in the food packaging industry with biodegradable and edible films. Biodegradable edible films and coatings are mainly made from carbohydrates, lipids and proteins and their mixtures. In recent decades, various carbohydrates from plant sources have been investigated and introduced as new compounds for the preparation of these films. Flaxseed gum is a white to cream-colored powder that dissolves in water and produces a gel, and is a desirable compound for forming films and coatings. Recently, through the integration of reinforcements or fillers with at least one nanometer dimension in the substrate of one or more natural biopolymers, the physicochemical, mechanical, optical, thermal and barrier properties of pure biofilms have been improved. The use of cellulose nanoparticles in biofilms as a reinforcing agent for polymer materials leads to the creation of composite films with better quality characteristics and leads to the creation of functionalization activities in film production. Therefore, the aim of this research was to produce and characterize edible and biodegradable film based on the combination of flaxseed gum and cellulose nanocrystals.
Materials and Methods
Cellulose nanocrystals (Degree of crystallinity: 42% and average particle size: 58 nm) were extracted from cotton linters. Glycerol and other chemicals used for this research were obtained from Merck, Germany. Flaxseeds were purchased from the local market of Shiraz (Iran). Bionanocomposite films were prepared from different ratios (0:100, 30:70, 50:50, 70:30 and 100:0) of flaxseed mucilage (2% w/v) and cellulose nanocrystal (6% w/v) solutions. The prepared solutions were poured on a petri dish with a diameter of 15 cm and dried in an oven at 80°C for 4 hours. Their physical, color and mechanical properties were investigated and the best ratio was selected for the preparation of bionanocomposite film. The produced films were subjected to different analysis to determine thickness, solubility, water absorption capacity, permeability to water vapor, tensile strength, elongation at break point, and colorimetry. The microstructure of the produced film was studied using a scanning electron microscopy (SEM).The average data were analyzed by analysis of variance in a completely randomized design using SPSS 22.0 software. Differences between treatments were expressed in Duncan's multiple range test at the 95% probability level (p<0.05) and the corresponding graphs were drawn with Excel 2013.
Results and Discussion
The results of the film thickness test showed that the film containing 100% mucilage has the lowest thickness and with the addition of cellulose nanocrystals, the thickness increased significantly (p<0.05). The results of the water solubility and water absorption capacity of the film samples showed that the addition of cellulose nanocrystals to the flaxseed mucilage film initially led to a significant decrease in the water solubility and water absorption capacity (p<0.05), so that the lowest level ofthese two physical parameters were obtained in the film containing the combination of 70% flaxseed mucilage and 30% cellulose nanocrystal, and then with the increase of cellulose nanocrystals, an increase in water solubility and water absorption capacity of the films was observed. Nanocrystal cellulose at low levels (30%) acted as a filler and was uniformly dispersed in the network of the film and by filling the empty pores of the biopolymer film based on flaxseed mucilage, it caused the transfer of water vapor more complicated and reduced the permeability to water vapor. However, its higher amount increased the permeability of the film to water vapor.The results showed that by adding cellulose nanocrystal to the film based on flaxseed mucilage and increasing its amount, the brightness of the films decreased and the intensity of redness, yellowness and turbidity of the films increased significantly (p<0.05). By combining flaxseed mucilage and cellulose nanocrystals in a ratio of 30:70, the best film was produced in terms of mechanical strength and stability against moisture and water vapor. The SEM image of this film showed a smooth, even surface and a uniform distribution of cellulose nanocrystals in the film network.
Conclusion
The results finally showed that the combination of flaxseed mucilage and cellulose nanocrystals in a ratio of 30:70 was able to produce a biodegradable and edible film with favorable structural and barrier properties. The characteristics of this film include; thickness (0.313mm), solubility (53.42%), water absorption capacity (44.44%), permeability to water vapor (0.350 g.m-1s-1Pa-1 × 10 -10), tensile strength (0.973 MPa), elongation at break point (30.52%) were obtained. The colorimetric indices L*, a*, b* and turbidity were determined as 79.73, 1.95, 3.48 and 1.335 mm-1 respectively.
Acknowledgement
The authors would like to express their sincere gratitude to Islamic Azad University, Sarvestan Branch.
Research Interests:
Introduction Free radicals originate from oxidation reactions decrease food quality and also promote incidence of various diseases such as cancer. In this regard, the use of natural compounds with antioxidant properties, such as... more
Introduction
Free radicals originate from oxidation reactions decrease food quality and also promote incidence of various diseases such as cancer. In this regard, the use of natural compounds with antioxidant properties, such as bioactive peptides, is of interest to many researchers. Food-derived bioactive peptides, can play an important role in the oxidative systems. Ultrasound, as a cheap and green technology, is widely used to extract proteins and antioxidant compounds. Ultrasound pretreatment before enzymatic hydrolysis can open the protein structure and increase the intensity of proteolysis by increasing the exposure of peptide bonds prone to enzymatic hydrolysis; which increases the production efficiency of bioactive peptides. Ultrasound treatment changes the three-dimensional structure of proteins. Therefore, a combination of pretreatment with ultrasound and sequential enzymatic hydrolysis can be a promising way to modify the function of proteins.
Materials and Methods
In this research the effect of hydrolysis time and ultrasonic pretreatment on enzymatic hydrolysis of edible mushroom protein by pancreatic enzyme to produce peptides with high antioxidant capacity was evaluated. First edible mushroom was turned into powder and then, in order to optimize the production of hydrolyzed proteins with maximum antioxidant activity, the hydrolysis was performed 30, 60, 90, 120, 150, 180 and 210 minutes with a ratio of enzyme to substrate of 1% (based on the result of previous research) and at 40°C in four conditions (1- without ultrasound pre-treatment, 2- with ultrasound pre-treatment with 40% power, 3- with ultrasound pre-treatment with 70% power and 4- with ultrasound pre-treatment with 100% power) by ultrasound probe in 5 minutes before adding the enzyme. In the next step, the antioxidant capacity of hydrolyzed proteins was measured at different times by DPPH free radical scavenging activity, iron ion reduction power, iron ion chelation and total antioxidant capacity.
Results
The results showed that the highest DPPH free radical scavenging activity in untreated and treated samples with 40, 70 and 100% ultrasound power were 69.1, 77.45, 79.07 and 80.27, respectively. In most of the hydrolysis times, DPPH free radical scavenging activity in ultrasound treatment with 100% power was higher than the samples treated with 40 and 70% power. The highest total antioxidant capacity in untreated and treated samples with 40, 70 and 100% ultrasound power were 0.871, 1.025, 1.05 and 1.2 (absorption at 695 nm), respectively. In most of the hydrolysis times, the total antioxidant capacity in the samples treated with ultrasound with 100% power was higher than the samples treated with 40 and 70% power. The results showed that the highest reducing power of Fe3+ in untreated and treated samples with 40, 70 and 100% ultrasound power were 2.03, 2.40, 2.44 and 2.51(absorption at 700 nm), respectively. The highest iron ion chelation power in untreated and treated samples with 40, 70 and 100% ultrasound power were 25.22, 30.40, 26.52 and 41.10%, respectively. By increasing the ultrasound power in most of the hydrolysis times, the chelating power of iron ions in the ultrasound treatment with 100% power was higher than the samples pretreated with 40 and 70% power. The results showed that samples pretreated with 100% power ultrasound have the highest antioxidant properties compared to samples without pretreatment and pretreated with 40% and 70% ultrasound power. Based on the results, using ultrasound treatment with 100% power and during hydrolysis time of 60 minutes, a product with high antioxidant capacity was obtained and selected as a suitable treatment.
Conclusion
The ultrasonic mechanism is attributed to its thermal effects, cavitation and mechanical efficiency, so that it can increase the mass transfer and increase the contact between the substrate and the enzyme or change the spatial structure of the substrate. The results showed that samples pretreated with ultrasound with 100% power have the highest antioxidant properties compared to samples without pretreatment and pretreated with 40 and 70% power. Therefore, the use of high-power ultrasonic pretreatment shortens the hydrolysis time to achieve peptides with higher antioxidant capacity and thus increases the efficiency of enzymatic hydrolysis.
Free radicals originate from oxidation reactions decrease food quality and also promote incidence of various diseases such as cancer. In this regard, the use of natural compounds with antioxidant properties, such as bioactive peptides, is of interest to many researchers. Food-derived bioactive peptides, can play an important role in the oxidative systems. Ultrasound, as a cheap and green technology, is widely used to extract proteins and antioxidant compounds. Ultrasound pretreatment before enzymatic hydrolysis can open the protein structure and increase the intensity of proteolysis by increasing the exposure of peptide bonds prone to enzymatic hydrolysis; which increases the production efficiency of bioactive peptides. Ultrasound treatment changes the three-dimensional structure of proteins. Therefore, a combination of pretreatment with ultrasound and sequential enzymatic hydrolysis can be a promising way to modify the function of proteins.
Materials and Methods
In this research the effect of hydrolysis time and ultrasonic pretreatment on enzymatic hydrolysis of edible mushroom protein by pancreatic enzyme to produce peptides with high antioxidant capacity was evaluated. First edible mushroom was turned into powder and then, in order to optimize the production of hydrolyzed proteins with maximum antioxidant activity, the hydrolysis was performed 30, 60, 90, 120, 150, 180 and 210 minutes with a ratio of enzyme to substrate of 1% (based on the result of previous research) and at 40°C in four conditions (1- without ultrasound pre-treatment, 2- with ultrasound pre-treatment with 40% power, 3- with ultrasound pre-treatment with 70% power and 4- with ultrasound pre-treatment with 100% power) by ultrasound probe in 5 minutes before adding the enzyme. In the next step, the antioxidant capacity of hydrolyzed proteins was measured at different times by DPPH free radical scavenging activity, iron ion reduction power, iron ion chelation and total antioxidant capacity.
Results
The results showed that the highest DPPH free radical scavenging activity in untreated and treated samples with 40, 70 and 100% ultrasound power were 69.1, 77.45, 79.07 and 80.27, respectively. In most of the hydrolysis times, DPPH free radical scavenging activity in ultrasound treatment with 100% power was higher than the samples treated with 40 and 70% power. The highest total antioxidant capacity in untreated and treated samples with 40, 70 and 100% ultrasound power were 0.871, 1.025, 1.05 and 1.2 (absorption at 695 nm), respectively. In most of the hydrolysis times, the total antioxidant capacity in the samples treated with ultrasound with 100% power was higher than the samples treated with 40 and 70% power. The results showed that the highest reducing power of Fe3+ in untreated and treated samples with 40, 70 and 100% ultrasound power were 2.03, 2.40, 2.44 and 2.51(absorption at 700 nm), respectively. The highest iron ion chelation power in untreated and treated samples with 40, 70 and 100% ultrasound power were 25.22, 30.40, 26.52 and 41.10%, respectively. By increasing the ultrasound power in most of the hydrolysis times, the chelating power of iron ions in the ultrasound treatment with 100% power was higher than the samples pretreated with 40 and 70% power. The results showed that samples pretreated with 100% power ultrasound have the highest antioxidant properties compared to samples without pretreatment and pretreated with 40% and 70% ultrasound power. Based on the results, using ultrasound treatment with 100% power and during hydrolysis time of 60 minutes, a product with high antioxidant capacity was obtained and selected as a suitable treatment.
Conclusion
The ultrasonic mechanism is attributed to its thermal effects, cavitation and mechanical efficiency, so that it can increase the mass transfer and increase the contact between the substrate and the enzyme or change the spatial structure of the substrate. The results showed that samples pretreated with ultrasound with 100% power have the highest antioxidant properties compared to samples without pretreatment and pretreated with 40 and 70% power. Therefore, the use of high-power ultrasonic pretreatment shortens the hydrolysis time to achieve peptides with higher antioxidant capacity and thus increases the efficiency of enzymatic hydrolysis.
Research Interests:
Introduction Today, carrots are widely used in freshly cut products, including ready to eat salads, however, its shelf life is reduced due to the damage caused on the texture of the product which accelerate the reduction of nutritional... more
Introduction
Today, carrots are widely used in freshly cut products, including ready to eat salads, however, its shelf life is reduced due to the damage caused on the texture of the product which accelerate the reduction of nutritional value as well as the growth of microorganisms, (Azizian et al., 2020). To increase the shelf life of freshly cut products, it is recommended to use coatings on the surface of these products. Alginate is a hydrophilic biopolymer and having unique colloidal characteristics, it demonstrates a suitable coating function. Olivas et al. (2008) showed that by coating fresh apple slices with alginate and antimicrobial agents increased the shelf life of apple and decreased weight loss. Among the native plants of Iran, we can mention the Oliveria plant, which belongs to the Amblifra family. The aerial parts of this plant have a significant amount of essential oils (EOs). Researches by Amin et al. (2005) on the antimicrobial properties of Oliveria essential oils have shown a broad-spectrum antimicrobial activity against all studied organisms, and this effect is comparable to that of commercial antibiotics. Packaging with modified atmosphere is one of the best ways to increase the shelf life of fruits and vegetables. The purpose of this study was to investigate the effect of alginate and Oliveria essential oils on the physicochemical and microbial characteristics of grated carrots in polypropylene packages with modified atmosphere during storage.
Methods
Essential oil of Oliveria plant was extracted, dehydrated by sodium sulfate and placed in sealed glass container and stored at 4˚C until using. Carrots prepared from Wilmoren cultivar. An industrial crusher crushed the carrots, and samples were coated by treatment solutions. Two treatments of coating were prepared, one as control with 0% and the other one with 1.5% alginate with stirring and moderate heat (50-60°C) (Lu et al., 2009). Then the Oliveria EO was added to the alginate solution at the specified concentration. The resulting solution was deaerated at 25˚C.
T1: control sample (without coating)
T2: 1.5% alginate
T3: 150 ppm Olivieria EO
T4: 250 ppm Olivieria EO
T5: 1.5% alginate and 150 ppm of Olivieria EO
T6: 1.5% alginate and 250 ppm of Olivieria EO
After weighing (250 g), the grated carrots (control and coated) were placed in 10 g polypropylene packages of suitable food grade in dimensions of 50 × 190 × 144 cm and the package was injected with 5% O2, 5% CO2 and 90% N2. The packages were then stored in the refrigerator for 12 days at 4±1˚C. All experiments were performed on days 1, 3, 6, 9, and 12.
Evaluation of Chemical, Microbial and Sensory Characteristics
A pH meter used for pH determination (Rad et al., 2020). The acidity measured based on Rocha et al. (2007) method.
The weight was reported using pre and post-storage weight. The carotenoid concentration calculated by Rocha et al. (2007) method. Total soluble solids determined by refractometer (Rad et al., 2020). Ascorbic acid content measured by Falahi et al. (2013) method. The L*, a*, b* and WI (white index) indicators of grated carrots evaluated by Hunter lab system. A 5-point hedonic test was used to assess sensory attributes(Ajnevardi et al., 2002). The internal gas concentration evaluated by Ullsten & Hedenqvist (2003) method. Total count microorganisms, mold, and yeast were counted according to the method of Azizian et al. (2020).
Data Analysis
This study was conducted in a completely randomized design with factorial form to investigate the effect of independent variables of type of alginate coating (2 levels), essential oil (3 levels) and time (5 levels) on the physicochemical properties of grated carrots (3 replications) and total counting, mold and yeast (2 replications). Mean comparison was performed using LSD test at 5% probability level and SPSS software was used to statistically analyze data.
Result
The results showed that the level of acidity, carotenoid and acid ascorbic, the amount of L* and sensory (color, quality, flavor, odor) scores reduced during time. By contrast the level of pH, weight loss, the amount of a*, b*, CO2, TSS and total counts increased (P<0.05). Also, with increasing the concentration of essential oils and alginates, the amount of acidity, carotenoids, ascorbic acid, L* increased and pH, weight loss, TSS, a*, b*, CO2 and total count decreased (P<0.05). Escherichia coli, mold and yeast count of the samples did not show any growth from the mentioned treatments until the 12th day. Overall, the Oliveria essential oil and alginate were effective in improving the properties of grated carrots under the modified atmosphere during storage.
Conclusion
The study showed that Oliveria EO and alginate added to grated carrots in modified atmosphere packaging during storage was effective in reducing respiration, water loss, microbial load and increased the shelf life. Treatment containing 1.5% alginate and 250 ppm Oliveria EO showed the best chemical, microbial and sensory characteristics. The results indicated that by packing under modified atmosphere and coating by alginate and Oliveria EO, a new carrot product provided to the market with maintaining durability and quality characteristics during storage.
Today, carrots are widely used in freshly cut products, including ready to eat salads, however, its shelf life is reduced due to the damage caused on the texture of the product which accelerate the reduction of nutritional value as well as the growth of microorganisms, (Azizian et al., 2020). To increase the shelf life of freshly cut products, it is recommended to use coatings on the surface of these products. Alginate is a hydrophilic biopolymer and having unique colloidal characteristics, it demonstrates a suitable coating function. Olivas et al. (2008) showed that by coating fresh apple slices with alginate and antimicrobial agents increased the shelf life of apple and decreased weight loss. Among the native plants of Iran, we can mention the Oliveria plant, which belongs to the Amblifra family. The aerial parts of this plant have a significant amount of essential oils (EOs). Researches by Amin et al. (2005) on the antimicrobial properties of Oliveria essential oils have shown a broad-spectrum antimicrobial activity against all studied organisms, and this effect is comparable to that of commercial antibiotics. Packaging with modified atmosphere is one of the best ways to increase the shelf life of fruits and vegetables. The purpose of this study was to investigate the effect of alginate and Oliveria essential oils on the physicochemical and microbial characteristics of grated carrots in polypropylene packages with modified atmosphere during storage.
Methods
Essential oil of Oliveria plant was extracted, dehydrated by sodium sulfate and placed in sealed glass container and stored at 4˚C until using. Carrots prepared from Wilmoren cultivar. An industrial crusher crushed the carrots, and samples were coated by treatment solutions. Two treatments of coating were prepared, one as control with 0% and the other one with 1.5% alginate with stirring and moderate heat (50-60°C) (Lu et al., 2009). Then the Oliveria EO was added to the alginate solution at the specified concentration. The resulting solution was deaerated at 25˚C.
T1: control sample (without coating)
T2: 1.5% alginate
T3: 150 ppm Olivieria EO
T4: 250 ppm Olivieria EO
T5: 1.5% alginate and 150 ppm of Olivieria EO
T6: 1.5% alginate and 250 ppm of Olivieria EO
After weighing (250 g), the grated carrots (control and coated) were placed in 10 g polypropylene packages of suitable food grade in dimensions of 50 × 190 × 144 cm and the package was injected with 5% O2, 5% CO2 and 90% N2. The packages were then stored in the refrigerator for 12 days at 4±1˚C. All experiments were performed on days 1, 3, 6, 9, and 12.
Evaluation of Chemical, Microbial and Sensory Characteristics
A pH meter used for pH determination (Rad et al., 2020). The acidity measured based on Rocha et al. (2007) method.
The weight was reported using pre and post-storage weight. The carotenoid concentration calculated by Rocha et al. (2007) method. Total soluble solids determined by refractometer (Rad et al., 2020). Ascorbic acid content measured by Falahi et al. (2013) method. The L*, a*, b* and WI (white index) indicators of grated carrots evaluated by Hunter lab system. A 5-point hedonic test was used to assess sensory attributes(Ajnevardi et al., 2002). The internal gas concentration evaluated by Ullsten & Hedenqvist (2003) method. Total count microorganisms, mold, and yeast were counted according to the method of Azizian et al. (2020).
Data Analysis
This study was conducted in a completely randomized design with factorial form to investigate the effect of independent variables of type of alginate coating (2 levels), essential oil (3 levels) and time (5 levels) on the physicochemical properties of grated carrots (3 replications) and total counting, mold and yeast (2 replications). Mean comparison was performed using LSD test at 5% probability level and SPSS software was used to statistically analyze data.
Result
The results showed that the level of acidity, carotenoid and acid ascorbic, the amount of L* and sensory (color, quality, flavor, odor) scores reduced during time. By contrast the level of pH, weight loss, the amount of a*, b*, CO2, TSS and total counts increased (P<0.05). Also, with increasing the concentration of essential oils and alginates, the amount of acidity, carotenoids, ascorbic acid, L* increased and pH, weight loss, TSS, a*, b*, CO2 and total count decreased (P<0.05). Escherichia coli, mold and yeast count of the samples did not show any growth from the mentioned treatments until the 12th day. Overall, the Oliveria essential oil and alginate were effective in improving the properties of grated carrots under the modified atmosphere during storage.
Conclusion
The study showed that Oliveria EO and alginate added to grated carrots in modified atmosphere packaging during storage was effective in reducing respiration, water loss, microbial load and increased the shelf life. Treatment containing 1.5% alginate and 250 ppm Oliveria EO showed the best chemical, microbial and sensory characteristics. The results indicated that by packing under modified atmosphere and coating by alginate and Oliveria EO, a new carrot product provided to the market with maintaining durability and quality characteristics during storage.
Research Interests:
Introduction Carotenoids have many effects on human health. These compounds are produced by plants and microalgae. The extraction of carotenoids from microalgae such as Chlorella has received much attention, since microalgae grow all... more
Introduction
Carotenoids have many effects on human health. These compounds are produced by plants and microalgae. The extraction of carotenoids from microalgae such as Chlorella has received much attention, since microalgae grow all year round (regardless of the season) and at a much faster rate than plants in non-arable lands. The aim of this research was to optimize the concentrations of nutrients (nitrogen and phosphorous) in the growth medium of microalgae with the objective of maximizing carotenoids content. At the optimized nutrient conditions, the effect of phytohormones on production of carotenoids using Chlorella sorokiniana IG-W-96 was investigated.
Materials and Methods
Chlorella sorokiniana IG-W-96 was cultivated in BG11 growth medium with light intensity of 25000 lux and light: dark cycle of 16: 8 supplied with compressed air flow of 0.5 vvm containing 6% vol carbon dioxide. Under three concentrations of nitrate (0.04, 0.25, 1.5 〖 g L〗^(-1)) and three concentrations of phophate (0.01, 0.04, 0.16 〖 g L〗^(-1)) and carotenoid concentration was measured. Full factorial experimnetal design was performed and the resuts of the experiments were analyzed using Minitab (ver. 21.01.1). Finally, the best concentrations of nitrate and phosphate were chosen for pigments production, and at that concentration, naphthalene acetic acid (0, 2.5, 5, 7.5, 10 and 12 ppm) was added to the culture medium to check its effect on pigments production. By measuring the dry weight of C. sorokiniana, its growth rate was determined. After extracting the pigments with solvent, the concentration of the pigments was determined by measuring the amount of light absorption.
Results and Discussion
Dry weight
The results showed that the highest amount of dry weight was related to the treatment with nitrate amount of 0.25〖 g L〗^(-1), and nitrate more and less than this amount caused a decrease in growth. This result was not dependent on the amount of phosphate and was true for all phosphate concentrations. Nitrate reduction from 1.5 to 0.25 〖 g L〗^(-1)increased the growth of microalgae up to 81.8%, so that the dry weight of 0.88〖 g L〗^(-1) reached 1.6 〖 g L〗^(-1). However, reduction of nitrate from 0.25 to 0.04 〖 g L〗^(-1) decreased the dry weight by 65.6%. In order to reach the maximum growth rate, it is necessary to determine the appropriate concentration of each nutrient.
Carotenoids
Unlike the dry weight, not only the pigment production did not decrease with the excessive of nitrate concentration, but also the maximum amount of pigment production was related to the treatment with the maximum amount of nitrate concentration. Based on the results obtained, the concentration of carotenoids was higher in the concentration of 1.5〖 g L〗^(-1) of nitrate and 0.04 〖 g L〗^(-1) of phosphate (6.7 〖 mg L〗^(-1)).
When the nitrate concentration was very low (0.04〖 g L〗^(-1)), changing the phosphate concentration had no significant effect on the production rate of any of the pigments. Only when the nitrate concentration was high (1.5 〖g L〗^(-1)), change in phosphate concentration caused a change in pigments concentration. The increase of phosphate concentration from 0.01 to 0.04 〖 g L〗^(-1)increased the carotenoids concentration to 1.65-fold. Of course, increasing phosphate concentration to 0.16 〖 g L〗^(-1)did not affect the pigments concentration.
Based on the statistical analysis, the P-value<0.05 indicated that the effect of the factors and the model was significant. In this situation, in order to increase the production of carotenoids, naphthalene acetic acid was added to the phytohormone culture medium. At the optimal concentration of 2.5 ppm of naphthalene acetic acid, the concentration of carotenoids increased by 26.71% and reached 8.49 〖 mg L〗^(-1). However, phytohormone had no significant effect on dry weight.
Conclusion
Carotenoid production using microalgae could be maximized through optimization of nutrients concentrations (nitrate and phosphate) in the growth medium. Phytohormones could further increase the prodcution of carotenoids at optimum concnetrations.
Carotenoids have many effects on human health. These compounds are produced by plants and microalgae. The extraction of carotenoids from microalgae such as Chlorella has received much attention, since microalgae grow all year round (regardless of the season) and at a much faster rate than plants in non-arable lands. The aim of this research was to optimize the concentrations of nutrients (nitrogen and phosphorous) in the growth medium of microalgae with the objective of maximizing carotenoids content. At the optimized nutrient conditions, the effect of phytohormones on production of carotenoids using Chlorella sorokiniana IG-W-96 was investigated.
Materials and Methods
Chlorella sorokiniana IG-W-96 was cultivated in BG11 growth medium with light intensity of 25000 lux and light: dark cycle of 16: 8 supplied with compressed air flow of 0.5 vvm containing 6% vol carbon dioxide. Under three concentrations of nitrate (0.04, 0.25, 1.5 〖 g L〗^(-1)) and three concentrations of phophate (0.01, 0.04, 0.16 〖 g L〗^(-1)) and carotenoid concentration was measured. Full factorial experimnetal design was performed and the resuts of the experiments were analyzed using Minitab (ver. 21.01.1). Finally, the best concentrations of nitrate and phosphate were chosen for pigments production, and at that concentration, naphthalene acetic acid (0, 2.5, 5, 7.5, 10 and 12 ppm) was added to the culture medium to check its effect on pigments production. By measuring the dry weight of C. sorokiniana, its growth rate was determined. After extracting the pigments with solvent, the concentration of the pigments was determined by measuring the amount of light absorption.
Results and Discussion
Dry weight
The results showed that the highest amount of dry weight was related to the treatment with nitrate amount of 0.25〖 g L〗^(-1), and nitrate more and less than this amount caused a decrease in growth. This result was not dependent on the amount of phosphate and was true for all phosphate concentrations. Nitrate reduction from 1.5 to 0.25 〖 g L〗^(-1)increased the growth of microalgae up to 81.8%, so that the dry weight of 0.88〖 g L〗^(-1) reached 1.6 〖 g L〗^(-1). However, reduction of nitrate from 0.25 to 0.04 〖 g L〗^(-1) decreased the dry weight by 65.6%. In order to reach the maximum growth rate, it is necessary to determine the appropriate concentration of each nutrient.
Carotenoids
Unlike the dry weight, not only the pigment production did not decrease with the excessive of nitrate concentration, but also the maximum amount of pigment production was related to the treatment with the maximum amount of nitrate concentration. Based on the results obtained, the concentration of carotenoids was higher in the concentration of 1.5〖 g L〗^(-1) of nitrate and 0.04 〖 g L〗^(-1) of phosphate (6.7 〖 mg L〗^(-1)).
When the nitrate concentration was very low (0.04〖 g L〗^(-1)), changing the phosphate concentration had no significant effect on the production rate of any of the pigments. Only when the nitrate concentration was high (1.5 〖g L〗^(-1)), change in phosphate concentration caused a change in pigments concentration. The increase of phosphate concentration from 0.01 to 0.04 〖 g L〗^(-1)increased the carotenoids concentration to 1.65-fold. Of course, increasing phosphate concentration to 0.16 〖 g L〗^(-1)did not affect the pigments concentration.
Based on the statistical analysis, the P-value<0.05 indicated that the effect of the factors and the model was significant. In this situation, in order to increase the production of carotenoids, naphthalene acetic acid was added to the phytohormone culture medium. At the optimal concentration of 2.5 ppm of naphthalene acetic acid, the concentration of carotenoids increased by 26.71% and reached 8.49 〖 mg L〗^(-1). However, phytohormone had no significant effect on dry weight.
Conclusion
Carotenoid production using microalgae could be maximized through optimization of nutrients concentrations (nitrate and phosphate) in the growth medium. Phytohormones could further increase the prodcution of carotenoids at optimum concnetrations.
Research Interests:
Introduction Phycocyanin is one of the pigments used in the food industry due to its antioxidant and antibacterial as well as coloring properties. This pigment is commercially produced from Spirulina platensis microalgae, in the form of... more
Introduction
Phycocyanin is one of the pigments used in the food industry due to its antioxidant and antibacterial as well as coloring properties. This pigment is commercially produced from Spirulina platensis microalgae, in the form of photoautotrophic cultures and in open environments in large ponds or pools in tropical or subtropical areas at the edges of oceans. Different techniques are used in order to extract phycocyanin from spirulina microalgae.. Each technique has its own advantages and disadvantages besides different efficiency. These methods include freezing-defrosting, enzymatic, ultrasound, high hydrostatic pressure, ultracentrifuge, ultra homogenization, extraction using water and various solvents. Of course recently, the production of recombinant phycocyanin has been considered as a suitable option for the production of heterotrophic phycocyanin. The purpose of the current research was to cultivate Spirulina platensis, evaluation of the microalgae growth process, and comparison of the efficiency of different methods in the extraction of phycocyanin pigment.
Materials and Methods
The pure sample of Spirulina platensis microalgae was prepared from Algaeology Laboratory, Biology Department of Tarbiat Modares University. For the cultivation of spirulina, Zarrouk culture medium with different compositions was used, and after cultivation in smaller scales (100 and 500 ml), the final cultivation was carried out in volumes of 5 and 50 liters. After cultivating the microalgae and exposing them to fluorescent light with appropriate light lux intensity (3500 to 8000) and a period of 12 hours of darkness and 12 hours of light, the samples were placed at 29 °C for 16 days. In order to evaluate the growth process of the algal mass, the absorbance of the solution containing the algal cells was read at a wavelength of 540 nm. After preparing the dry mass of spirulina microalgae, four methods of ultrasound, freezing-defrosting, enzymatic and mineral solvent technique were used to extract phycocyanin. In the next steps, the efficiency of each method was evaluated by measuring the concentration and purity of phycocyanin. In addition, the effect of applying the purification process by ammonium sulfate on the concentration and purity of the extracted pigment was also evaluated. This research was conducted in a completely randomized design and SPSS and EXCEL softwares were used for statistical analysis and drawing of diagram, respectively. Data were analyzed using one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level.
Results and Discussion
The results showed that microalgae growth from day 0 to 14 had an upward trend and the resulting changes were significant at all times, except days 14 and 16 (p<0.05). Also, after passing the short resting phase (2 days), the microalgae entered the logarithmic growth phase and continued to grow until the 14th day, but between the 14th and 16th days, the growth was almost constant. In the following, it was found that the mass produced after 16 days is 1120 mg/l. The concentration of phycocyanin extracted in enzymatic and ultrasound methods (1.815 and 1.786 mg/ml, respectively) had no significant difference (p>0.05) and was at a higher level than the other two methods (p<0.05); In addition, the pigment concentration was higher in the freezing-defrosting technique (1.535 mg/ml) than in the mineral solvent method (1.121 mg/ml). After purification of the pigment using ammonium sulfate, the pigment concentration and purity increased significantly in each method (p<0.05). The results of this research showed that by choosing the optimal method and applying the purification process using ammonium sulfate, the extraction efficiency of phycocyanin from Spirulina microalgae (Spirulina platensis) could be increased.
Conclusion
Based on the results of this research, the growth trend of Spirulina platensis in Zarrouk culture medium was ascending first and then constant (during 16 days). Ultrasound technique and enzymatic method (lysozyme enzyme) to extract phycocyanin pigment from Spirulina platensis microalgae have more efficiency than freezing-defrosting and inorganic solvent (hydrochloric acid) methods. Also, purification of the extracted pigment using 40% ammonium sulfate increases the concentration and purity of phycocyanin in each method.
Phycocyanin is one of the pigments used in the food industry due to its antioxidant and antibacterial as well as coloring properties. This pigment is commercially produced from Spirulina platensis microalgae, in the form of photoautotrophic cultures and in open environments in large ponds or pools in tropical or subtropical areas at the edges of oceans. Different techniques are used in order to extract phycocyanin from spirulina microalgae.. Each technique has its own advantages and disadvantages besides different efficiency. These methods include freezing-defrosting, enzymatic, ultrasound, high hydrostatic pressure, ultracentrifuge, ultra homogenization, extraction using water and various solvents. Of course recently, the production of recombinant phycocyanin has been considered as a suitable option for the production of heterotrophic phycocyanin. The purpose of the current research was to cultivate Spirulina platensis, evaluation of the microalgae growth process, and comparison of the efficiency of different methods in the extraction of phycocyanin pigment.
Materials and Methods
The pure sample of Spirulina platensis microalgae was prepared from Algaeology Laboratory, Biology Department of Tarbiat Modares University. For the cultivation of spirulina, Zarrouk culture medium with different compositions was used, and after cultivation in smaller scales (100 and 500 ml), the final cultivation was carried out in volumes of 5 and 50 liters. After cultivating the microalgae and exposing them to fluorescent light with appropriate light lux intensity (3500 to 8000) and a period of 12 hours of darkness and 12 hours of light, the samples were placed at 29 °C for 16 days. In order to evaluate the growth process of the algal mass, the absorbance of the solution containing the algal cells was read at a wavelength of 540 nm. After preparing the dry mass of spirulina microalgae, four methods of ultrasound, freezing-defrosting, enzymatic and mineral solvent technique were used to extract phycocyanin. In the next steps, the efficiency of each method was evaluated by measuring the concentration and purity of phycocyanin. In addition, the effect of applying the purification process by ammonium sulfate on the concentration and purity of the extracted pigment was also evaluated. This research was conducted in a completely randomized design and SPSS and EXCEL softwares were used for statistical analysis and drawing of diagram, respectively. Data were analyzed using one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level.
Results and Discussion
The results showed that microalgae growth from day 0 to 14 had an upward trend and the resulting changes were significant at all times, except days 14 and 16 (p<0.05). Also, after passing the short resting phase (2 days), the microalgae entered the logarithmic growth phase and continued to grow until the 14th day, but between the 14th and 16th days, the growth was almost constant. In the following, it was found that the mass produced after 16 days is 1120 mg/l. The concentration of phycocyanin extracted in enzymatic and ultrasound methods (1.815 and 1.786 mg/ml, respectively) had no significant difference (p>0.05) and was at a higher level than the other two methods (p<0.05); In addition, the pigment concentration was higher in the freezing-defrosting technique (1.535 mg/ml) than in the mineral solvent method (1.121 mg/ml). After purification of the pigment using ammonium sulfate, the pigment concentration and purity increased significantly in each method (p<0.05). The results of this research showed that by choosing the optimal method and applying the purification process using ammonium sulfate, the extraction efficiency of phycocyanin from Spirulina microalgae (Spirulina platensis) could be increased.
Conclusion
Based on the results of this research, the growth trend of Spirulina platensis in Zarrouk culture medium was ascending first and then constant (during 16 days). Ultrasound technique and enzymatic method (lysozyme enzyme) to extract phycocyanin pigment from Spirulina platensis microalgae have more efficiency than freezing-defrosting and inorganic solvent (hydrochloric acid) methods. Also, purification of the extracted pigment using 40% ammonium sulfate increases the concentration and purity of phycocyanin in each method.
Research Interests:
Introduction Consumer demand for healthy food free of chemical preservatives and environmental concerns with plastic packaging environments are analyzed, which can be replaced by aquatic environments that can be contaminated, for the... more
Introduction
Consumer demand for healthy food free of chemical preservatives and environmental concerns with plastic packaging environments are analyzed, which can be replaced by aquatic environments that can be contaminated, for the development of bio-based packaging materials. Natural polymers have the ability to be biodegradable due to the presence of oxygen or nitrogen atoms in their main polymer chain compared to the dominant carbon-carbon bonds in fossil-based polymers. Among the various biopolymers used to prepare multilayer films, polysaccharides are considered as the main components of the film due to their abundance and non-toxicity. These films generally have good mechanical strength, moderate physical properties, and most importantly, are edible and easily degradable. However, they are very brittle and hydrophilic, and these properties are undesirable in food packaging applications. Among polysaccharides, agar, commercially extracted from seaweed, is one of the most common and widely studied base materials. Agar is insoluble in cold water, but soluble in water at 90-100°C. When making an agar film, the solution and casting surface must be kept above the agarose gel setting temperature to avoid premature gelation. Compared to other biopolymers, agar is more stable at low pH and high temperature. This thermoplastic and biocompatible polysaccharide creates films with high mechanical strength, transparency and moderate barrier properties to carbon dioxide and oxygen, and most importantly, it is edible and easily biodegradable. Mixing agar with other polymers such as polyvinyl alcohol (PVA) and polyethylene improves the mechanical, thermal and biodegradability properties of bio composites. The main goal of this study is to make biofilms for use in packaging industries with agar polymer extracted from macroalgae species Acanthophora sp. Agar was extracted by sodium hydroxide/heating method and the film was prepared in combination with industrial polymer PVA and glycerol.
Materials and Methods
To make biofilms based on agar polymer, firstly, optimization of agar polymer extraction from macroalgae species Acanthophora sp. was done by sodium hydroxide/heating method, and in the next step, total phenolic compounds and the amount of soluble protein in extracted agar were measured. In the next step, glycerol with 30% by weight was used as a softener and PVA polymer with a weight ratio of 25% to the dry weight of agar powder was used to make bio composite by solvent casting method, in order to strengthen the mechanical and physical properties of bio composites. Characterization tests of the prepared composites included: XRD, FTIR and Tensile test. Laboratory tests include; The percentage of solubility in water and degree of swelling for all bio-composites were evaluated to determine the optimal physical properties of bio-films.
Results and Discussion:
he results showed that; 15% extraction efficiency was obtained for sodium hydroxide/heating pretreatment method. The results of measuring the amount of total phenolic compounds in agar solution extracted by sodium hydroxide/heating method showed that the number of phenolic compounds in agar solution was 0.077 ± 0.004 in terms of mg of gallic acid/g of agar. The results of measuring the amount of protein in extracted agar determined by Bradford method showed that the agar solution contains 0.040 ± 0.019 mg/ml of protein. A decrease in the swelling rate and an increase in the water solubility of the agar bio composite occurred with the addition of glycerol and PVA polymer. The results of the tensile test showed that the addition of glycerol, a small hydrophilic molecule, to the agar bio composite leads to a decrease in the elastic modulus and an increase in flexibility. Adding PVA to agar/glycerol biofilm caused a decrease in the amount of elastic modulus and percentage of flexibility, which is the main factor of this phenomenon, the low values of elastic modulus and flexibility of PVA. Finally, the results confirm the use of these coatings for packing fruits and vegetables in tropical regions by increasing their shelf life for at least 5 days at 25°C.
Consumer demand for healthy food free of chemical preservatives and environmental concerns with plastic packaging environments are analyzed, which can be replaced by aquatic environments that can be contaminated, for the development of bio-based packaging materials. Natural polymers have the ability to be biodegradable due to the presence of oxygen or nitrogen atoms in their main polymer chain compared to the dominant carbon-carbon bonds in fossil-based polymers. Among the various biopolymers used to prepare multilayer films, polysaccharides are considered as the main components of the film due to their abundance and non-toxicity. These films generally have good mechanical strength, moderate physical properties, and most importantly, are edible and easily degradable. However, they are very brittle and hydrophilic, and these properties are undesirable in food packaging applications. Among polysaccharides, agar, commercially extracted from seaweed, is one of the most common and widely studied base materials. Agar is insoluble in cold water, but soluble in water at 90-100°C. When making an agar film, the solution and casting surface must be kept above the agarose gel setting temperature to avoid premature gelation. Compared to other biopolymers, agar is more stable at low pH and high temperature. This thermoplastic and biocompatible polysaccharide creates films with high mechanical strength, transparency and moderate barrier properties to carbon dioxide and oxygen, and most importantly, it is edible and easily biodegradable. Mixing agar with other polymers such as polyvinyl alcohol (PVA) and polyethylene improves the mechanical, thermal and biodegradability properties of bio composites. The main goal of this study is to make biofilms for use in packaging industries with agar polymer extracted from macroalgae species Acanthophora sp. Agar was extracted by sodium hydroxide/heating method and the film was prepared in combination with industrial polymer PVA and glycerol.
Materials and Methods
To make biofilms based on agar polymer, firstly, optimization of agar polymer extraction from macroalgae species Acanthophora sp. was done by sodium hydroxide/heating method, and in the next step, total phenolic compounds and the amount of soluble protein in extracted agar were measured. In the next step, glycerol with 30% by weight was used as a softener and PVA polymer with a weight ratio of 25% to the dry weight of agar powder was used to make bio composite by solvent casting method, in order to strengthen the mechanical and physical properties of bio composites. Characterization tests of the prepared composites included: XRD, FTIR and Tensile test. Laboratory tests include; The percentage of solubility in water and degree of swelling for all bio-composites were evaluated to determine the optimal physical properties of bio-films.
Results and Discussion:
he results showed that; 15% extraction efficiency was obtained for sodium hydroxide/heating pretreatment method. The results of measuring the amount of total phenolic compounds in agar solution extracted by sodium hydroxide/heating method showed that the number of phenolic compounds in agar solution was 0.077 ± 0.004 in terms of mg of gallic acid/g of agar. The results of measuring the amount of protein in extracted agar determined by Bradford method showed that the agar solution contains 0.040 ± 0.019 mg/ml of protein. A decrease in the swelling rate and an increase in the water solubility of the agar bio composite occurred with the addition of glycerol and PVA polymer. The results of the tensile test showed that the addition of glycerol, a small hydrophilic molecule, to the agar bio composite leads to a decrease in the elastic modulus and an increase in flexibility. Adding PVA to agar/glycerol biofilm caused a decrease in the amount of elastic modulus and percentage of flexibility, which is the main factor of this phenomenon, the low values of elastic modulus and flexibility of PVA. Finally, the results confirm the use of these coatings for packing fruits and vegetables in tropical regions by increasing their shelf life for at least 5 days at 25°C.
Research Interests:
Introduction The increase in people's awareness of the negative effects of chemical preservatives has led to more research on the antimicrobial effect of plant essential oils and their potential to be used as preservative compounds.... more
Introduction
The increase in people's awareness of the negative effects of chemical preservatives has led to more research on the antimicrobial effect of plant essential oils and their potential to be used as preservative compounds. Strawberry (Fragaria ananassa cv. qingxiang) is one of the most popular and widely consumed berries due to its taste, sweetness and healthy function. The taste of strawberry is related to its hardness, viscosity, sugars, protein, total soluble solid, titratable acidity content and minerals like P, K, Ca and Fe. It is a good source of polyphenolic compounds such as flavanols and has antioxidant activity. This, together with higher vitamin C content in strawberries, contributes beneficial effects on the maintenance of consumer health. Strawberry has higher antioxidant activities than orange, grape, banana, apple, etc. Strawberries are among the fruits sensitive to mechanical and physiological damage and have a fast metabolism and deterioration during the storage period. For this reason, it is necessary to use safe methods to control spoilage and maintain the quality of strawberry fruit during storage.
Materials and Methods
The experiment was conducted in a completely randomized design, in a 5 x 4 factorial scheme (5 treatments x 4 periods evaluated), with four replications The first variable was the type of material with different concentrations in five levels including 0, 0.3%, 0.6% carvacrol, the combination of chitosan with 0.3% and 0.6% carvacrol, and the second variable was storage time in four periods including 0, 10, 20, 30 days of storage. The harvested fruits were kept at 4°C and with a relative humidity of 90±5% and parameters such as weight loss, pH, firmness of the fruit tissue, acidity (TA), soluble solids (TSS) and taste index, vitamin C, phenol and flavonoid, fruit shelf life (number of days) during the storage period were investigated and studied.
Results and Discussion
The ANOVA results showed that the effect of the type of treatment and storage time on all investigated traits except for the firmness of the fruit texture was significant at the probability level of 1%. The fruits treated with the combination of chitosan and carvacrol 0.6% had more texture firmness, vitamin C, total phenol content and the amount of soluble solids and better shelf life than the control. In all four storage times, the highest content of total phenol (2.49 mg of gallic acid per 100 gr FW), total flavonoid (0.435 mg of Quercetin per 100 gr FW) and firmness (3.80 N) was related to the combined treatment of chitosan with carvacrol 0.6% and the lowest amount was related to the control. The firmness of the fruit tissue gradually decreased during storage, but this process was observed at a significantly slower rate in the treated fruits.
Conclusion
Considering the increase of 10 and 12 days of shelf life post- harvest of the combined treatment of chitosan + 0.6% carvacrol compared to other treatments and the control, hence the application of chitosan pre harvest and the use of 0.6% carvacrol edible coatings can be recommended as a safe and low-cost strategy to increase the shelf life post harvesting of 'Parus ' strawberry cultivar.
The increase in people's awareness of the negative effects of chemical preservatives has led to more research on the antimicrobial effect of plant essential oils and their potential to be used as preservative compounds. Strawberry (Fragaria ananassa cv. qingxiang) is one of the most popular and widely consumed berries due to its taste, sweetness and healthy function. The taste of strawberry is related to its hardness, viscosity, sugars, protein, total soluble solid, titratable acidity content and minerals like P, K, Ca and Fe. It is a good source of polyphenolic compounds such as flavanols and has antioxidant activity. This, together with higher vitamin C content in strawberries, contributes beneficial effects on the maintenance of consumer health. Strawberry has higher antioxidant activities than orange, grape, banana, apple, etc. Strawberries are among the fruits sensitive to mechanical and physiological damage and have a fast metabolism and deterioration during the storage period. For this reason, it is necessary to use safe methods to control spoilage and maintain the quality of strawberry fruit during storage.
Materials and Methods
The experiment was conducted in a completely randomized design, in a 5 x 4 factorial scheme (5 treatments x 4 periods evaluated), with four replications The first variable was the type of material with different concentrations in five levels including 0, 0.3%, 0.6% carvacrol, the combination of chitosan with 0.3% and 0.6% carvacrol, and the second variable was storage time in four periods including 0, 10, 20, 30 days of storage. The harvested fruits were kept at 4°C and with a relative humidity of 90±5% and parameters such as weight loss, pH, firmness of the fruit tissue, acidity (TA), soluble solids (TSS) and taste index, vitamin C, phenol and flavonoid, fruit shelf life (number of days) during the storage period were investigated and studied.
Results and Discussion
The ANOVA results showed that the effect of the type of treatment and storage time on all investigated traits except for the firmness of the fruit texture was significant at the probability level of 1%. The fruits treated with the combination of chitosan and carvacrol 0.6% had more texture firmness, vitamin C, total phenol content and the amount of soluble solids and better shelf life than the control. In all four storage times, the highest content of total phenol (2.49 mg of gallic acid per 100 gr FW), total flavonoid (0.435 mg of Quercetin per 100 gr FW) and firmness (3.80 N) was related to the combined treatment of chitosan with carvacrol 0.6% and the lowest amount was related to the control. The firmness of the fruit tissue gradually decreased during storage, but this process was observed at a significantly slower rate in the treated fruits.
Conclusion
Considering the increase of 10 and 12 days of shelf life post- harvest of the combined treatment of chitosan + 0.6% carvacrol compared to other treatments and the control, hence the application of chitosan pre harvest and the use of 0.6% carvacrol edible coatings can be recommended as a safe and low-cost strategy to increase the shelf life post harvesting of 'Parus ' strawberry cultivar.
Research Interests:
Introduction Bakery products such as cakes are consumed in a relatively large amount all over the world due to their ready to eat format. Among different foods, bakery products provide a great opportunity to use edible portions of seeds,... more
Introduction
Bakery products such as cakes are consumed in a relatively large amount all over the world due to their ready to eat format. Among different foods, bakery products provide a great opportunity to use edible portions of seeds, vegetables or other unconventional food sources. On the other hand, cakes are susceptible to oxidation due to high amounts of fat and consequently reduce shelf life. Therefore, due to the high nutritional value of cake, improving its characteristics seems necessary. Wheat germ is the richest known source of vitamin E of plant origin. Consumption of wheat germ can prevent artery- clogging and also helps fight against free radical damage and procrastination are effective in the aging process of cells and preventing coronary disease. Despite the beneficial properties of wheat germ, it is difficult to keep it raw in the formulation of crops due to the presence of high unsaturated fatty acids and lipase enzymes. However, by performing thermal processes such as steam, fluidized substrate or thermal dryer, enzymes such as lipase and lipoxygenase can be deactivated. In this study, the effect of adding wheat germ as a rich source of fiber, tocopherols and essential fatty acids as well as ascorbyl palmitate as antioxidant compound on the qualitative and structural properties of cake was investigated.
Materials and Methods
In this study, five treatments of oil cake including control, ascorbyl palmitate (100 ppm), wheat germ (5, 10 and 15%), were prepared and physic-chemical properties including the moisture, firmness and volume of cake at the beginning of storage period, peroxide number and acidity during 14-day storage period were investigated. In order to evaluate the texture of the cake, texture analyzer was performed with dimensions of 25 mm and penetration of 50% in the sample at a speed of 2 mm/s and a 30-second stop between the first and second compressions. The specific volume of the produced samples and moisture of the middle part of the samples were measured 3 hours after baking.
Results and Discussion
The results showed that addition of L-ascorbyl palmitate had no significant effect on moisture content, hardness and cake volume. However, wheat germ increased hardness (in amounts more than 5%), decreased moisture content and specific volume of cake. Also, with increasing the amount of wheat germ, a significant decrease in peroxide and acidity of the samples were observed during the storage period. However, the values of the mentioned indices in the sample containing palmitate ascorbyl were lower than those containing wheat germ. According to the results, it seems that the sample containing 5% processed wheat germ can be recommended as a suitable formulation for cake enrichment.
Conclusion
Considering that oxidation of cakes and reduction shelf life in different type of cakes are probable due to the presence of considerable amounts of fatty acids, in this study the effect of adding L-ascorbyl palmitate as a common antioxidant and processed wheat germ due to its antioxidant behavior on the moisture content, hardness, specific volume, texture and shelf-life characteristics of the oil cake was investigated. The overall results show that by adding L-ascorbyl palmitate, there was no significant effect on moisture content, hardness and specific volume. However, processed wheat germ increased hardness (in amounts more than 5%), decreased moisture content and specific volume of cake. Also, with increasing the amount of wheat germ, a significant decrease in peroxide value and acidity of the cake was observed during the storage period. However, the values of moisture content, hardness and specific volume in the sample containing palmitate ascorbyl were lower than samples containing wheat germ. According to the results, it seems that sample containing 5% processed wheat germ can be recommended as a suitable formulation for cake enrichment and artificial antioxidant replacement.
Bakery products such as cakes are consumed in a relatively large amount all over the world due to their ready to eat format. Among different foods, bakery products provide a great opportunity to use edible portions of seeds, vegetables or other unconventional food sources. On the other hand, cakes are susceptible to oxidation due to high amounts of fat and consequently reduce shelf life. Therefore, due to the high nutritional value of cake, improving its characteristics seems necessary. Wheat germ is the richest known source of vitamin E of plant origin. Consumption of wheat germ can prevent artery- clogging and also helps fight against free radical damage and procrastination are effective in the aging process of cells and preventing coronary disease. Despite the beneficial properties of wheat germ, it is difficult to keep it raw in the formulation of crops due to the presence of high unsaturated fatty acids and lipase enzymes. However, by performing thermal processes such as steam, fluidized substrate or thermal dryer, enzymes such as lipase and lipoxygenase can be deactivated. In this study, the effect of adding wheat germ as a rich source of fiber, tocopherols and essential fatty acids as well as ascorbyl palmitate as antioxidant compound on the qualitative and structural properties of cake was investigated.
Materials and Methods
In this study, five treatments of oil cake including control, ascorbyl palmitate (100 ppm), wheat germ (5, 10 and 15%), were prepared and physic-chemical properties including the moisture, firmness and volume of cake at the beginning of storage period, peroxide number and acidity during 14-day storage period were investigated. In order to evaluate the texture of the cake, texture analyzer was performed with dimensions of 25 mm and penetration of 50% in the sample at a speed of 2 mm/s and a 30-second stop between the first and second compressions. The specific volume of the produced samples and moisture of the middle part of the samples were measured 3 hours after baking.
Results and Discussion
The results showed that addition of L-ascorbyl palmitate had no significant effect on moisture content, hardness and cake volume. However, wheat germ increased hardness (in amounts more than 5%), decreased moisture content and specific volume of cake. Also, with increasing the amount of wheat germ, a significant decrease in peroxide and acidity of the samples were observed during the storage period. However, the values of the mentioned indices in the sample containing palmitate ascorbyl were lower than those containing wheat germ. According to the results, it seems that the sample containing 5% processed wheat germ can be recommended as a suitable formulation for cake enrichment.
Conclusion
Considering that oxidation of cakes and reduction shelf life in different type of cakes are probable due to the presence of considerable amounts of fatty acids, in this study the effect of adding L-ascorbyl palmitate as a common antioxidant and processed wheat germ due to its antioxidant behavior on the moisture content, hardness, specific volume, texture and shelf-life characteristics of the oil cake was investigated. The overall results show that by adding L-ascorbyl palmitate, there was no significant effect on moisture content, hardness and specific volume. However, processed wheat germ increased hardness (in amounts more than 5%), decreased moisture content and specific volume of cake. Also, with increasing the amount of wheat germ, a significant decrease in peroxide value and acidity of the cake was observed during the storage period. However, the values of moisture content, hardness and specific volume in the sample containing palmitate ascorbyl were lower than samples containing wheat germ. According to the results, it seems that sample containing 5% processed wheat germ can be recommended as a suitable formulation for cake enrichment and artificial antioxidant replacement.
Research Interests:
Introduction Yogurt is one of the most widely consumed fermented milk products, which, like any other dairy products, is prone to spoilage and poor quality. On the other hand consumers have become more cautious about their diet and... more
Introduction
Yogurt is one of the most widely consumed fermented milk products, which, like any other dairy products, is prone to spoilage and poor quality. On the other hand consumers have become more cautious about their diet and health. Their is an increasing demand for food products with higher nutritional values and health benefits. The continuous improvement of the production process and the quality of yogurt is at the heart of manufacturers’ concerns. Also, finding a safe, cheap and affordable solution that, in addition to controlling blood sugar and preventing the complications of diabetes, relieves the pain of diabetic patients; has always been of interest to researchers. The medicinal plant Bitter gourd (Momordica charantia L.) from the cucurbitaceae family is used in traditional medicine to control blood sugar. Carla fruit is a rich source of phytochemical compounds such as proteins, steroids, alkaloids, mineral compounds, lipids, triterpenoids and polyphenols. Functional yogurt is one of the dairy products that can contain bioactive compounds in order to increase its acceptability and improve its nutritional and medicinal properties. Therefore, this study was carried out with the aim of producing colored yogurt containing Carla fruit powder in order to increase the variety of appearance, marketability of the product and improve the nutritional characteristics of yogurt with emphasis on the consumption of novel product.
Materials and Methods
In this study, the effects of adding Carla powder to yogurt were investigated with the aim of producing a beneficial food for diabetics. Carla fruit was collected from the medicinal plants collection of the Agriculture Institute, Research Institute of Zabol, Zabol, Iran. Then it was washed with water and cut into thin layers. These parts were completely dried in an electric oven at 40 ºC for 48 hours and pulverized with an electric mill. Carla fruit powder was added to the samples in four levels of 0 (control), 0.2, 0.4 and 0.6%. Physicochemical properties of samples such as pH, acidity, viscosity (using Brookfield spindle viscometer) and water holding capacity were measured. Total phenol content was measured by Folin Ciocalteu reagent method. Antioxidant properties were investigated by scavenging rate of DPPH free radicals. The results were analyzed by SPSS version 21 statistical software at the probability level of 5% (P˂ 0.05). Duncan's multiple range test was performed to determine the statistically significant difference between the means.
Results and Discussion
The results of this study showed that the highest pH (4.17) was detected in the control and the addition of Carla fruit powder led to a decrease in pH. Storage time also lower the pH in yogurt samples. The highest acidity (1.3%) was measured in the treatment containing 0.6% Carla fruit powder and the lowest (0.59%) was in the control. It means that adding Carla powder to yogurt leads to an increase in acidity. The highest amount of phenolic compounds (475.63 μg equivalent of gallic acid/ml yogurt), was calculated in a sample containing 0.6% of Carla fruit powder. However, extended storage time, decreases the amount of phenolic compounds. By increasing the percentage of Carla fruit powder in yogurt samples, the amount of antioxidant activity increased. So that the highest antioxidant activity (93%) was related to the treatment containing 0.6% Carla powder on the 28th day of the storage. In the present study, the highest percentage of water holding capacity (84%) was observed in samples containing 0.6% Carla powder. The lowest water holding capacity (57.61%) was measured in the control sample at the first day of storage.
Conclusion
According to the results of this study, adding Carla powder to yogurt at the level of 0.6%, in addition to maintaining appearance properties, can increase its physicochemical properties and produce a novel food. In general, Carla powder can play a significant role in improving the textural properties of yogurt, and by increasing the viscosity and the water holding capacity, can reduce the negative effects of the storage period.
Acknowledgement
This research was conducted with the financial support by Research Institute of Zabol (Grant code: IR-RIOZ-GR-9027).
Yogurt is one of the most widely consumed fermented milk products, which, like any other dairy products, is prone to spoilage and poor quality. On the other hand consumers have become more cautious about their diet and health. Their is an increasing demand for food products with higher nutritional values and health benefits. The continuous improvement of the production process and the quality of yogurt is at the heart of manufacturers’ concerns. Also, finding a safe, cheap and affordable solution that, in addition to controlling blood sugar and preventing the complications of diabetes, relieves the pain of diabetic patients; has always been of interest to researchers. The medicinal plant Bitter gourd (Momordica charantia L.) from the cucurbitaceae family is used in traditional medicine to control blood sugar. Carla fruit is a rich source of phytochemical compounds such as proteins, steroids, alkaloids, mineral compounds, lipids, triterpenoids and polyphenols. Functional yogurt is one of the dairy products that can contain bioactive compounds in order to increase its acceptability and improve its nutritional and medicinal properties. Therefore, this study was carried out with the aim of producing colored yogurt containing Carla fruit powder in order to increase the variety of appearance, marketability of the product and improve the nutritional characteristics of yogurt with emphasis on the consumption of novel product.
Materials and Methods
In this study, the effects of adding Carla powder to yogurt were investigated with the aim of producing a beneficial food for diabetics. Carla fruit was collected from the medicinal plants collection of the Agriculture Institute, Research Institute of Zabol, Zabol, Iran. Then it was washed with water and cut into thin layers. These parts were completely dried in an electric oven at 40 ºC for 48 hours and pulverized with an electric mill. Carla fruit powder was added to the samples in four levels of 0 (control), 0.2, 0.4 and 0.6%. Physicochemical properties of samples such as pH, acidity, viscosity (using Brookfield spindle viscometer) and water holding capacity were measured. Total phenol content was measured by Folin Ciocalteu reagent method. Antioxidant properties were investigated by scavenging rate of DPPH free radicals. The results were analyzed by SPSS version 21 statistical software at the probability level of 5% (P˂ 0.05). Duncan's multiple range test was performed to determine the statistically significant difference between the means.
Results and Discussion
The results of this study showed that the highest pH (4.17) was detected in the control and the addition of Carla fruit powder led to a decrease in pH. Storage time also lower the pH in yogurt samples. The highest acidity (1.3%) was measured in the treatment containing 0.6% Carla fruit powder and the lowest (0.59%) was in the control. It means that adding Carla powder to yogurt leads to an increase in acidity. The highest amount of phenolic compounds (475.63 μg equivalent of gallic acid/ml yogurt), was calculated in a sample containing 0.6% of Carla fruit powder. However, extended storage time, decreases the amount of phenolic compounds. By increasing the percentage of Carla fruit powder in yogurt samples, the amount of antioxidant activity increased. So that the highest antioxidant activity (93%) was related to the treatment containing 0.6% Carla powder on the 28th day of the storage. In the present study, the highest percentage of water holding capacity (84%) was observed in samples containing 0.6% Carla powder. The lowest water holding capacity (57.61%) was measured in the control sample at the first day of storage.
Conclusion
According to the results of this study, adding Carla powder to yogurt at the level of 0.6%, in addition to maintaining appearance properties, can increase its physicochemical properties and produce a novel food. In general, Carla powder can play a significant role in improving the textural properties of yogurt, and by increasing the viscosity and the water holding capacity, can reduce the negative effects of the storage period.
Acknowledgement
This research was conducted with the financial support by Research Institute of Zabol (Grant code: IR-RIOZ-GR-9027).
Research Interests:
Introduction Ultrafiltration is one of the most common membrane processes in the dairy industry, especially for condensing and separating milk components. Using this process, several products can be produced, including milk concentrate... more
Introduction
Ultrafiltration is one of the most common membrane processes in the dairy industry, especially for condensing and separating milk components. Using this process, several products can be produced, including milk concentrate used for cheese production, low-lactose dairy products, milk protein concentrate, and serum proteins for dietary supplements. The efficiency and cost of a membrane process depend on the percentage of rejection of the soluble components. Therefore, the use of concentrated milk made by ultrafiltration in the production of various dairy products depends on the efficiency of the membrane process and the changes in milk components during this process. On the one hand, the physicochemical properties of camel milk are different from those of cow milk, especially in terms of type and amount of protein. Because significant differences exist between the physicochemical properties of camel and cow milk, likely, the membrane processing conditions and the physicochemical properties of their products will be different completely. Although many studies have been conducted on the efficacy of the ultrafiltration processing of cow milk, there is no information about the efficacy of camel milk ultrafiltration, and most of the research done regarding optimizing is based on classical algorithms, Therefore, in this study, the effects of transmembrane pressure and temperature on the solutes rejection (protein, lactose, ash, and total solids) during camel milk ultrafiltration process were investigated, Then, these properties were optimized using particle swarm algorithm. Also, because the performance of the particle swarm algorithm is highly dependent on related parameters such as the number of iterations, the number of particles, accelerate constant, inertia weight, and velocity of the particles, so before optimization, the effect of these parameters on optimal responses were examined by partial least squares regression (PLS).
Materials and Methods
In this study, a pilot crossflow ultrafiltration system was used. A UF membrane (Model 3838 HFK-131, Koch membrane systems, Inc., USA) made of polysulfone amid (PSA) with MWCO of 20 kDa was applied. Camel milk was purchased from a local market in Mashhad and for camel skim milk production, its fat was separated by a pilot plant milk fat separator in the Food Research Complex, Ferdowsi University of Mashhad. The weight percentages of protein, fat, lactose, ash, and total solids of UF permeate samples were measured by ISO 8968-1:2014, ISO 1211: 2010, ISO 26462/IDF 214:2010, ISO 5544:2008, and ISO 6731:2010 at two replications, respectively. the process treatments were performed in the form of a central composite design (CCD) (5 replications at the central point) for two independent variables at three levels so that the total number of 13 treatments was obtained. The data were modeled using the statistical software of Design Expert (version 11) based on the response surface methodology and each of the response variables in the form of a regression model was presented as a function of independent variables.
Results and Discussion
The rejection of total solids and protein of the tested samples varied in the range of 45.4-51.03% and 94.09-97.51%, respectively. It means that in each TMP and T, more than 45% of the total solids and 94% of the protein of camel milk were kept by the membrane. The results also showed that none of the linear, quadratic and interactive effects of TMP and T on the total solids and protein rejections were not significant. According to the results, the RL reduced with increasing T. Increasing the TMP also led to a reduction at high T and an increase in RL rate of the samples at lover T. Also, the effect of TMP on RA showed a non-linear trend, so that TMP at high T led to an increase, and at low T, it led to a reduction in the RA of the samples.
Conclusion
The optimization results with the particle swarm algorithm showed that this algorithm has a high convergence speed and by recognizing and analyzing its parameters, the optimal conditions can be easily found. The optimum ultrafiltration conditions in this study with the lowest RL and RA were determined as 80 kPa TMP and 29.85 ͦ C T.
Ultrafiltration is one of the most common membrane processes in the dairy industry, especially for condensing and separating milk components. Using this process, several products can be produced, including milk concentrate used for cheese production, low-lactose dairy products, milk protein concentrate, and serum proteins for dietary supplements. The efficiency and cost of a membrane process depend on the percentage of rejection of the soluble components. Therefore, the use of concentrated milk made by ultrafiltration in the production of various dairy products depends on the efficiency of the membrane process and the changes in milk components during this process. On the one hand, the physicochemical properties of camel milk are different from those of cow milk, especially in terms of type and amount of protein. Because significant differences exist between the physicochemical properties of camel and cow milk, likely, the membrane processing conditions and the physicochemical properties of their products will be different completely. Although many studies have been conducted on the efficacy of the ultrafiltration processing of cow milk, there is no information about the efficacy of camel milk ultrafiltration, and most of the research done regarding optimizing is based on classical algorithms, Therefore, in this study, the effects of transmembrane pressure and temperature on the solutes rejection (protein, lactose, ash, and total solids) during camel milk ultrafiltration process were investigated, Then, these properties were optimized using particle swarm algorithm. Also, because the performance of the particle swarm algorithm is highly dependent on related parameters such as the number of iterations, the number of particles, accelerate constant, inertia weight, and velocity of the particles, so before optimization, the effect of these parameters on optimal responses were examined by partial least squares regression (PLS).
Materials and Methods
In this study, a pilot crossflow ultrafiltration system was used. A UF membrane (Model 3838 HFK-131, Koch membrane systems, Inc., USA) made of polysulfone amid (PSA) with MWCO of 20 kDa was applied. Camel milk was purchased from a local market in Mashhad and for camel skim milk production, its fat was separated by a pilot plant milk fat separator in the Food Research Complex, Ferdowsi University of Mashhad. The weight percentages of protein, fat, lactose, ash, and total solids of UF permeate samples were measured by ISO 8968-1:2014, ISO 1211: 2010, ISO 26462/IDF 214:2010, ISO 5544:2008, and ISO 6731:2010 at two replications, respectively. the process treatments were performed in the form of a central composite design (CCD) (5 replications at the central point) for two independent variables at three levels so that the total number of 13 treatments was obtained. The data were modeled using the statistical software of Design Expert (version 11) based on the response surface methodology and each of the response variables in the form of a regression model was presented as a function of independent variables.
Results and Discussion
The rejection of total solids and protein of the tested samples varied in the range of 45.4-51.03% and 94.09-97.51%, respectively. It means that in each TMP and T, more than 45% of the total solids and 94% of the protein of camel milk were kept by the membrane. The results also showed that none of the linear, quadratic and interactive effects of TMP and T on the total solids and protein rejections were not significant. According to the results, the RL reduced with increasing T. Increasing the TMP also led to a reduction at high T and an increase in RL rate of the samples at lover T. Also, the effect of TMP on RA showed a non-linear trend, so that TMP at high T led to an increase, and at low T, it led to a reduction in the RA of the samples.
Conclusion
The optimization results with the particle swarm algorithm showed that this algorithm has a high convergence speed and by recognizing and analyzing its parameters, the optimal conditions can be easily found. The optimum ultrafiltration conditions in this study with the lowest RL and RA were determined as 80 kPa TMP and 29.85 ͦ C T.
Research Interests:
Introduction Cronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies... more
Introduction
Cronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. In this study, the effect of a Lactiplantibacillus plantarum strain (M17) along with the standard strain Lactobacillus plantarum (ATCC 8014) and the well-characterized probiotic strain Lactobacillus rhamnosus GG on the adhesion of C. sakazakii to intestinal epithelial cells was analyzed.
Materials and Methods
Acid and bile tolerance of M17 was evaluated in the presence of pepsin and pancreatin. L-arginine hydrolysis was investigated using an arginine-including medium. Auto-aggregation and co-aggregation assays were performed by absorbance measurement. Minimum inhibitory concentrations of the antimicrobials recommended by the European Food Safety Authority were established. Total lactic acid and the ratio of D/L lactate isomers were determined with a Megazyme enzymatic kit. The ability of the isolate to produce biogenic amines was tested by qualitative and quantitative monitoring. Hemolysis was assessed phenotypically on MRS agar enriched with sheep blood. The strain was tested for its capability to adhere to mucin and Caco-2 cells. The antagonistic effects of the strain against C. sakazakii were further evaluated in vitro on mucin and cultured Caco-2 cells. The LAB strain was added simultaneously with, before, and after C. sakazakii to Caco-2 cells for competition, exclusion and displacement assays, respectively. Data analysis was performed in R using one-way analysis of variance, and the experimental groups were compared with the controls using Tukey’s test. P values <0.05 were considered statistically significant.
Results and Discussion
There was no significant difference in the survival rate of M17 and L. plantarum ATCC 8014 at pH = 4. After 2 h of incubation at pH = 2.5, the survival rate of L. plantarum ATCC 8014 was estimated to be higher than strain M17, but this difference was not significant. After 4 hours of incubation at pH = 8, M17 showed a higher survival rate than L. plantarum ATCC 8014, and this difference was significant after transfer from pH = 4. These results confirm the appropriate viability of M17 in the gastrointestinal tract. Both M17 and L. plantarum ATCC 8014 developed the color yellow in the L-arginine hydrolysis assay, which confirms the safety of these strains. The percentage of auto-aggregation for M17, L. plantarum ATCC 8014, and Lactobacillus rhamnosus LGG was estimated at 24.38, 25.28, and 32 after 6 hours, respectively, and no statistically significant difference between the two isolates were noticed. Given the auto-aggregation and co-aggregation parameters of M17, this strain may constitute a defense mechanism against C. sakazakii. Strain M17 showed resistance to kanamycin and clindamycin antibiotics. With intrinsic resistance, the risk of transferring resistance genes is not only speculative, but practically impossible. Intrinsic resistance of lactic acid bacteria may be considered desirable because it ensures their survival when the host is treated with antibiotics. Both D and L isomers of lactic acid were produced by the studied strains. In humans, D(-)-lactic acidosis is a rare metabolic complication that has only been reported in individuals with short bowel syndrome). Clinical studies have shown that the consumption of probiotic bacteria producing D(-)-lactic acid is safe for children and does not cause a long-term increase in blood D(-)-lactic acid. The reference L. plantarum strain and M17 did not produce biogenic amine precursors, and had no ß-hemolytic activity. Mucin adhesion assay exhibited that M17 has less adhesion (12.10 ± 1.14 %) than L. plantarum ATCC 8014 (13.33 ± 2.30 %) and LGG (15.93 ± 2.06 %) although these differences were not statistically significant. However, the amount of adhesion for the positive control sample Escherichia coli K12 (25.19 ± 4.40 %) was significantly higher than those of the other strains. Compared to the positive control, M17 had a significantly lower adhesion rate (6.8 ± 1.41) to CaCo-2 cells. This value was estimated at 13.77 ± 3.53 % for the reference strain and 21.6 ± 7.54 % for Lactobacillus fermentum PCC (positive control). In antagonistic assays, M17 was able to reduce the adhesion of C. sakazakii to mucin and CaCo-2 cells in all three methods of exclusion/inhibition, competition and displacement. Statistical analysis of the results does not show a significant difference between M17 and LGG. Therefore, the performance of M17 is similar to that of the standard probiotic LGG.
Conclusion
Lactic acid bacteria with acceptable ability to adhere to epithelial cells can be suitable for colonization in the intestine. They can act as a barrier to fight pathogens through various competitive mechanisms, such as co-aggregation with pathogens and adhesion. The M17 strain has an acceptable immune profile and probiotic properties because it shows an acceptable antagonistic activity against C. sakazakii invasion.
Acknowledgement
This study was supported by Ferdowsi University of Mashhad (Research affairs) [project No.:46718] and the research infrastructure at the University of Copenhagen.
Cronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. In this study, the effect of a Lactiplantibacillus plantarum strain (M17) along with the standard strain Lactobacillus plantarum (ATCC 8014) and the well-characterized probiotic strain Lactobacillus rhamnosus GG on the adhesion of C. sakazakii to intestinal epithelial cells was analyzed.
Materials and Methods
Acid and bile tolerance of M17 was evaluated in the presence of pepsin and pancreatin. L-arginine hydrolysis was investigated using an arginine-including medium. Auto-aggregation and co-aggregation assays were performed by absorbance measurement. Minimum inhibitory concentrations of the antimicrobials recommended by the European Food Safety Authority were established. Total lactic acid and the ratio of D/L lactate isomers were determined with a Megazyme enzymatic kit. The ability of the isolate to produce biogenic amines was tested by qualitative and quantitative monitoring. Hemolysis was assessed phenotypically on MRS agar enriched with sheep blood. The strain was tested for its capability to adhere to mucin and Caco-2 cells. The antagonistic effects of the strain against C. sakazakii were further evaluated in vitro on mucin and cultured Caco-2 cells. The LAB strain was added simultaneously with, before, and after C. sakazakii to Caco-2 cells for competition, exclusion and displacement assays, respectively. Data analysis was performed in R using one-way analysis of variance, and the experimental groups were compared with the controls using Tukey’s test. P values <0.05 were considered statistically significant.
Results and Discussion
There was no significant difference in the survival rate of M17 and L. plantarum ATCC 8014 at pH = 4. After 2 h of incubation at pH = 2.5, the survival rate of L. plantarum ATCC 8014 was estimated to be higher than strain M17, but this difference was not significant. After 4 hours of incubation at pH = 8, M17 showed a higher survival rate than L. plantarum ATCC 8014, and this difference was significant after transfer from pH = 4. These results confirm the appropriate viability of M17 in the gastrointestinal tract. Both M17 and L. plantarum ATCC 8014 developed the color yellow in the L-arginine hydrolysis assay, which confirms the safety of these strains. The percentage of auto-aggregation for M17, L. plantarum ATCC 8014, and Lactobacillus rhamnosus LGG was estimated at 24.38, 25.28, and 32 after 6 hours, respectively, and no statistically significant difference between the two isolates were noticed. Given the auto-aggregation and co-aggregation parameters of M17, this strain may constitute a defense mechanism against C. sakazakii. Strain M17 showed resistance to kanamycin and clindamycin antibiotics. With intrinsic resistance, the risk of transferring resistance genes is not only speculative, but practically impossible. Intrinsic resistance of lactic acid bacteria may be considered desirable because it ensures their survival when the host is treated with antibiotics. Both D and L isomers of lactic acid were produced by the studied strains. In humans, D(-)-lactic acidosis is a rare metabolic complication that has only been reported in individuals with short bowel syndrome). Clinical studies have shown that the consumption of probiotic bacteria producing D(-)-lactic acid is safe for children and does not cause a long-term increase in blood D(-)-lactic acid. The reference L. plantarum strain and M17 did not produce biogenic amine precursors, and had no ß-hemolytic activity. Mucin adhesion assay exhibited that M17 has less adhesion (12.10 ± 1.14 %) than L. plantarum ATCC 8014 (13.33 ± 2.30 %) and LGG (15.93 ± 2.06 %) although these differences were not statistically significant. However, the amount of adhesion for the positive control sample Escherichia coli K12 (25.19 ± 4.40 %) was significantly higher than those of the other strains. Compared to the positive control, M17 had a significantly lower adhesion rate (6.8 ± 1.41) to CaCo-2 cells. This value was estimated at 13.77 ± 3.53 % for the reference strain and 21.6 ± 7.54 % for Lactobacillus fermentum PCC (positive control). In antagonistic assays, M17 was able to reduce the adhesion of C. sakazakii to mucin and CaCo-2 cells in all three methods of exclusion/inhibition, competition and displacement. Statistical analysis of the results does not show a significant difference between M17 and LGG. Therefore, the performance of M17 is similar to that of the standard probiotic LGG.
Conclusion
Lactic acid bacteria with acceptable ability to adhere to epithelial cells can be suitable for colonization in the intestine. They can act as a barrier to fight pathogens through various competitive mechanisms, such as co-aggregation with pathogens and adhesion. The M17 strain has an acceptable immune profile and probiotic properties because it shows an acceptable antagonistic activity against C. sakazakii invasion.
Acknowledgement
This study was supported by Ferdowsi University of Mashhad (Research affairs) [project No.:46718] and the research infrastructure at the University of Copenhagen.
Research Interests:
Introduction Oxidation of lipids results in changes that may affect the nutritional quality, wholesomeness, colour, flavour and texture of food. The aim of this study was to investigate the type and amount of phenolic compounds in... more
Introduction
Oxidation of lipids results in changes that may affect the nutritional quality, wholesomeness, colour, flavour and texture of food. The aim of this study was to investigate the type and amount of phenolic compounds in ethanolic extract of aloe vera gel as a source of natural antioxidant and its effect on the oxidative stability of soybean oil.
Using synthetic antioxidant due to the possibility of toxic and carcinogenic effects is limited. Thus, it is important to find an alternative to synthetic antioxidants by natural antioxidant. Different intrinsic and extrinsic factors may initiate the oxidation of lipids. The initial products of oxidation are tasteless and odorless and after degradation and production of secondary products, the off-flavors and off-odors will appeared in edible oils. This is a great concern in food industry, because it decreases the shelf life of food products. Free radicals are produced during chain reactions in lipid oxidation process. To avoid this, synthetic antioxidants are usually used which are sensible to heat and are hazardous to human health and may cause cancer. Polyphenols have antioxidant activity and absorb free radicals. Thus, the vegetable oils rich in polyphenols can affect human health. In this research, we aimed to investigate the application of natural extract of aloe vera gel as a natural antioxidant to avoid soy oil oxidation and to compare it with synthetic antioxidants.
The rate of oxidation reaction can be delayed by adding antioxidants. Consumers today tend to use natural antioxidants instead of synthetics. The overall purpose of this study was to investigate the effect of adding ethanolic extract of aloe vera gel as natural antioxidant on improving the stability of soybean oil.
Materials and Methods
The compounds in ethanolic extract of aloe vera gel were determined using GC / MS. The antioxidant activity was evaluated by the method of DPPH. For this purpose, ethanolic extracts of aloe vera gel were added to soybean oil in four different concentrations (500, 1000, 1500, 2000 ppm) and peroxide value, acidity, thiobarbituric acid, total phenol, oxidative stability to Rancimat method, fatty acid profile and sensory evaluation were performed on soybean oil samples and compared with the control sample containing 120 ppm BHA and soybean oil sample without adding antioxidants during 30, 60 and 90 days of storage at 25 ° C.
Results and Discussion
The results showed that by increasing the concentration of aloe vera extracts from 500 to 2000 ppm, the oxidation rate decreases during 90 days of storage, the amount of peroxide, thiobarbituric acid and acidity of soybean oil containing 2000 ppm ethanolic extract of aloe vera gel was lower than the control sample containing 120 ppm BHA. The total phenol content and free radical scavenging and stability to oxidative degradation by Rancimat method in soybean oil sample containing 2000 ppm aloe vera ethanol extract was higher than soybean oil samples containing BHA120 ppm. Evaluation of sensory properties showed that no significant difference was observed between the sensory properties of the oil sample containing 2000 ppm ethanolic extract of aloe vera gel and the control soybean oil sample of BHA120 ppm.
Conclusion
Considering that the sample of soybean oil containing 2000 ppm ethanolic extract of aloe vera gel had higher phenol content and free radical scavenging and more antioxidant properties than the control sample, it did not differ significantly from the control sample. Qualitative and health properties were selected as the superior treatment. The results of this study showed that the ethanolic extract of aloe vera gel can be used as a natural antioxidant instead of conventional synthetic antioxidants in the oil industry and to prevent oxidative spoilage of the oil in a desirable way. Therefore, it might be employed as a natural antioxidant in foods, particularly those containing edible oils.
Oxidation of lipids results in changes that may affect the nutritional quality, wholesomeness, colour, flavour and texture of food. The aim of this study was to investigate the type and amount of phenolic compounds in ethanolic extract of aloe vera gel as a source of natural antioxidant and its effect on the oxidative stability of soybean oil.
Using synthetic antioxidant due to the possibility of toxic and carcinogenic effects is limited. Thus, it is important to find an alternative to synthetic antioxidants by natural antioxidant. Different intrinsic and extrinsic factors may initiate the oxidation of lipids. The initial products of oxidation are tasteless and odorless and after degradation and production of secondary products, the off-flavors and off-odors will appeared in edible oils. This is a great concern in food industry, because it decreases the shelf life of food products. Free radicals are produced during chain reactions in lipid oxidation process. To avoid this, synthetic antioxidants are usually used which are sensible to heat and are hazardous to human health and may cause cancer. Polyphenols have antioxidant activity and absorb free radicals. Thus, the vegetable oils rich in polyphenols can affect human health. In this research, we aimed to investigate the application of natural extract of aloe vera gel as a natural antioxidant to avoid soy oil oxidation and to compare it with synthetic antioxidants.
The rate of oxidation reaction can be delayed by adding antioxidants. Consumers today tend to use natural antioxidants instead of synthetics. The overall purpose of this study was to investigate the effect of adding ethanolic extract of aloe vera gel as natural antioxidant on improving the stability of soybean oil.
Materials and Methods
The compounds in ethanolic extract of aloe vera gel were determined using GC / MS. The antioxidant activity was evaluated by the method of DPPH. For this purpose, ethanolic extracts of aloe vera gel were added to soybean oil in four different concentrations (500, 1000, 1500, 2000 ppm) and peroxide value, acidity, thiobarbituric acid, total phenol, oxidative stability to Rancimat method, fatty acid profile and sensory evaluation were performed on soybean oil samples and compared with the control sample containing 120 ppm BHA and soybean oil sample without adding antioxidants during 30, 60 and 90 days of storage at 25 ° C.
Results and Discussion
The results showed that by increasing the concentration of aloe vera extracts from 500 to 2000 ppm, the oxidation rate decreases during 90 days of storage, the amount of peroxide, thiobarbituric acid and acidity of soybean oil containing 2000 ppm ethanolic extract of aloe vera gel was lower than the control sample containing 120 ppm BHA. The total phenol content and free radical scavenging and stability to oxidative degradation by Rancimat method in soybean oil sample containing 2000 ppm aloe vera ethanol extract was higher than soybean oil samples containing BHA120 ppm. Evaluation of sensory properties showed that no significant difference was observed between the sensory properties of the oil sample containing 2000 ppm ethanolic extract of aloe vera gel and the control soybean oil sample of BHA120 ppm.
Conclusion
Considering that the sample of soybean oil containing 2000 ppm ethanolic extract of aloe vera gel had higher phenol content and free radical scavenging and more antioxidant properties than the control sample, it did not differ significantly from the control sample. Qualitative and health properties were selected as the superior treatment. The results of this study showed that the ethanolic extract of aloe vera gel can be used as a natural antioxidant instead of conventional synthetic antioxidants in the oil industry and to prevent oxidative spoilage of the oil in a desirable way. Therefore, it might be employed as a natural antioxidant in foods, particularly those containing edible oils.
Research Interests:
Introduction Due to the importance of product appearance quality in product grading and the impact of factors such as area, uniformity, and various defects on the product quality, and also, the ability to recognize these features at a... more
Introduction
Due to the importance of product appearance quality in product grading and the impact of factors such as area, uniformity, and various defects on the product quality, and also, the ability to recognize these features at a very low cost, image processing techniques, is one of the methods used to evaluate food quality. Therefore, in this study, a non-destructive image processing method was used to investigate the factors affecting the color and shrinkage of apple slices during drying.
Materials and Methods
Golden delicious apples were used in this research. The central part of the apple (including the rivet, seeds, and tail) was removed by a kernel separator and sliced into 3, 5, and 7mm thickness and approximately 7 mm diameter slices using a hand slicer without separating the skin. Three temperatures of 60, 70, and 80 °C were used to dry the samples. To determine the moisture content of a sliced apple, the samples were first weighed on a digital scale, then placed in a dryer, and the experiment was continued until the samples reached equilibrium mass. Due to the high importance of moisture ratio in controlling the drying process, moisture rate (MR) and moisture content (MC) were calculated, and samples were taken to investigate the amount of surface shrinkage, general color changes and browning index. After extracting L*, a*, and b* values, total color changes and browning index (to show the intensity of brown color in the product) for all samples before and after drying were calculated and evaluated to describe color changes after drying.
Results and Discussion
The drying kinetics results showed that the drying process significantly depends on the thickness of the samples. According to drying curves, at the early stages of drying, the decrease in humidity occurs more severely and the graph has a steeper slope, but as the process continues and the moisture content of the product decreases, the slope of the curve decreases. In the early stages of drying, due to the presence of water inside the fresh fruit cells, there is a pressure balance between the fruit and the surrounding environment, which causes the fruit to remain swollen. However, as the drying time progressed, contractile stresses are created, which cause superficial shrinkage. In this study, it was observed that increasing the thickness from 3mm to 7mm, reduced the final shrinkage on the surface of apple slices by 11% at 60 °C, 12% at 70 °C, and 13% at 80 °C. After moisture leaves the surface of the product and heat penetrates into the product, moisture begins to leave the product by conducting interstitial convection. When moisture moves to the surface, the mechanical balance and consequently the textural structure of the sample is disturbed due to the creation of different spaces in thickness. According to the results, increasing drying time and thus decreasing the moisture content, increases the percentage of apple shrinkage. On the other hand, at a certain thickness, with increasing temperature, the percentage of shrinkage changes in the thickness of the product decreases. Therefore, at thicknesses of 3, 5, and 7 mm, the increase in temperature from 60°C to 80°C, decreased the amount of shrinkage thickness by 16, 12, and 8%, respectively. It is in higher thicknesses that react with heat and change the color of the fruit due to the Maillard reaction. After complete drying of apple samples, the highest amount of color change was related to the thickness of 7 mm and a temperature of 80°C, which was equal to 1.254. Also, the lowest rate of discoloration of apple slices in a thickness of 3 mm and a temperature of 60 °C was 0.889. The browning index (Bi) in the high thickness of apple slices is less affected by the process temperature due to the increase in moisture level. For this reason, the rate of browning was very low among the experimental samples and the highest rate of browning was related to the thickness of 7 mm and the temperature of 80 °C was 585/2559. Also, the lowest rate of browning of apple slices was observed in the thickness of 3 mm and the temperature of 60 °C was 584.254.
Conclusion
Finally, it was found that the thickness and temperature factors can have an effect on the quality of product during drying process. The results of this study can provide a cheap and fast way to control the quality of fruits during drying and help producers of these products select the main process factors that affect the final quality.
Due to the importance of product appearance quality in product grading and the impact of factors such as area, uniformity, and various defects on the product quality, and also, the ability to recognize these features at a very low cost, image processing techniques, is one of the methods used to evaluate food quality. Therefore, in this study, a non-destructive image processing method was used to investigate the factors affecting the color and shrinkage of apple slices during drying.
Materials and Methods
Golden delicious apples were used in this research. The central part of the apple (including the rivet, seeds, and tail) was removed by a kernel separator and sliced into 3, 5, and 7mm thickness and approximately 7 mm diameter slices using a hand slicer without separating the skin. Three temperatures of 60, 70, and 80 °C were used to dry the samples. To determine the moisture content of a sliced apple, the samples were first weighed on a digital scale, then placed in a dryer, and the experiment was continued until the samples reached equilibrium mass. Due to the high importance of moisture ratio in controlling the drying process, moisture rate (MR) and moisture content (MC) were calculated, and samples were taken to investigate the amount of surface shrinkage, general color changes and browning index. After extracting L*, a*, and b* values, total color changes and browning index (to show the intensity of brown color in the product) for all samples before and after drying were calculated and evaluated to describe color changes after drying.
Results and Discussion
The drying kinetics results showed that the drying process significantly depends on the thickness of the samples. According to drying curves, at the early stages of drying, the decrease in humidity occurs more severely and the graph has a steeper slope, but as the process continues and the moisture content of the product decreases, the slope of the curve decreases. In the early stages of drying, due to the presence of water inside the fresh fruit cells, there is a pressure balance between the fruit and the surrounding environment, which causes the fruit to remain swollen. However, as the drying time progressed, contractile stresses are created, which cause superficial shrinkage. In this study, it was observed that increasing the thickness from 3mm to 7mm, reduced the final shrinkage on the surface of apple slices by 11% at 60 °C, 12% at 70 °C, and 13% at 80 °C. After moisture leaves the surface of the product and heat penetrates into the product, moisture begins to leave the product by conducting interstitial convection. When moisture moves to the surface, the mechanical balance and consequently the textural structure of the sample is disturbed due to the creation of different spaces in thickness. According to the results, increasing drying time and thus decreasing the moisture content, increases the percentage of apple shrinkage. On the other hand, at a certain thickness, with increasing temperature, the percentage of shrinkage changes in the thickness of the product decreases. Therefore, at thicknesses of 3, 5, and 7 mm, the increase in temperature from 60°C to 80°C, decreased the amount of shrinkage thickness by 16, 12, and 8%, respectively. It is in higher thicknesses that react with heat and change the color of the fruit due to the Maillard reaction. After complete drying of apple samples, the highest amount of color change was related to the thickness of 7 mm and a temperature of 80°C, which was equal to 1.254. Also, the lowest rate of discoloration of apple slices in a thickness of 3 mm and a temperature of 60 °C was 0.889. The browning index (Bi) in the high thickness of apple slices is less affected by the process temperature due to the increase in moisture level. For this reason, the rate of browning was very low among the experimental samples and the highest rate of browning was related to the thickness of 7 mm and the temperature of 80 °C was 585/2559. Also, the lowest rate of browning of apple slices was observed in the thickness of 3 mm and the temperature of 60 °C was 584.254.
Conclusion
Finally, it was found that the thickness and temperature factors can have an effect on the quality of product during drying process. The results of this study can provide a cheap and fast way to control the quality of fruits during drying and help producers of these products select the main process factors that affect the final quality.
Research Interests:
Introduction Potato strips are one of the most widely consumed products, and due to their high oil content, they have caused public health concerns. Therefore, efforts to reduce oil absorption can alleviate these concerns to some extent.... more
Introduction
Potato strips are one of the most widely consumed products, and due to their high oil content, they have caused public health concerns. Therefore, efforts to reduce oil absorption can alleviate these concerns to some extent. Edible coating is an effective way to reduce oil uptake, because the oil absorption is a surface phenomenon. Edible coatings should adhere well to the surface of the product and provide a uniform and complete coverage for the product. Preventing the migration of oxygen, carbon dioxide, aromas, oils, moisture, improving the appearance of food and mechanical properties. In this study, the possibility of reducing oil absorption in French fries was investigated using okra mucilage and chitosan as edible coatings.
Material and Methods
The okra was washed and then cut into about 1 cm pieces and poured into containers with lids. Then water in a ratio of 2:1 weight of okra was added to the container and completely covered its surface. The okra were refrigerated for 72 hours until the mucilage was completely extracted. Then the mucilage was smoothed. This solution was considered as 100% mucilage solution. To prepare a 50% solution of okra mucilage, 100% solution was mixed with an equal amount of distilled water and filtered. To produce a solution of 0.75 and 1.5% of chitosan, 7.5 and 15 g of chitosan powder was dissolved in 1000 ml of 1% acetic acid and then adjusted to pH 5. Then 5 g of glycerol was added as a plasticizer. The potato slices were first blanched in 0.5% calcium chloride solution at 90°C for 5 minutes. Then, they were immersed in coating solutions at 60°C for 5 minutes. After coating, the potato strips were fried at 180°C using a fryer and then various characteristics including coating percentage, oil absorption, and moisture content, texture firmness, peroxide value, acid number, color indices and sensory properties were examined. Design Expert 8.0.7.1 software was used to analyze the results and to draw the curves.
Results and Discission
The results showed that the increasing the amount of chitosan led to better coating formation in comparison with okra. The highest coverage was observed in the concentration of 1.2% chitosan and 0% okra mucilage (2.38%) and the lowest was observed in the control sample (0.11%). It was also observed that with increasing the concentration of chitosan and okra mucilage, the amount of oil absorption decreases. However, the amount of oil absorption in high concentrations of okra mucilage increased slightly. The highest oil uptake in the control sample was 20% and the lowest was observed in the sample of fried strips covered with 41% okra mucilage and 1.5% chitosan at 15.44%. The obtained model of oxidation index was not significant. The effect of okra mucilage and chitosan concentration on the texture of the samples (p <0.05) and the color indices of a* (p<0.01) and L* (p <0.05) were significant. For sensory attributes, the highest and the lowest taste score was observed for samples coated with 100% okra mucilage and 0.75% chitosan and samples coated with 18% okra mucilage and 0% chitosan respectively.
Conclusion
The aim of this project was to reduce the oil absorption of fried potato strips by coating them with chitosan and okra mucilage. Optimization to minimize the consumption of okra and chitosan mucilage showed that coating with 74% okra and 0.89% chitosan is suitable for coating potato slices. The desirability of this optimization was 71%, which is a reasonable percentage.
Potato strips are one of the most widely consumed products, and due to their high oil content, they have caused public health concerns. Therefore, efforts to reduce oil absorption can alleviate these concerns to some extent. Edible coating is an effective way to reduce oil uptake, because the oil absorption is a surface phenomenon. Edible coatings should adhere well to the surface of the product and provide a uniform and complete coverage for the product. Preventing the migration of oxygen, carbon dioxide, aromas, oils, moisture, improving the appearance of food and mechanical properties. In this study, the possibility of reducing oil absorption in French fries was investigated using okra mucilage and chitosan as edible coatings.
Material and Methods
The okra was washed and then cut into about 1 cm pieces and poured into containers with lids. Then water in a ratio of 2:1 weight of okra was added to the container and completely covered its surface. The okra were refrigerated for 72 hours until the mucilage was completely extracted. Then the mucilage was smoothed. This solution was considered as 100% mucilage solution. To prepare a 50% solution of okra mucilage, 100% solution was mixed with an equal amount of distilled water and filtered. To produce a solution of 0.75 and 1.5% of chitosan, 7.5 and 15 g of chitosan powder was dissolved in 1000 ml of 1% acetic acid and then adjusted to pH 5. Then 5 g of glycerol was added as a plasticizer. The potato slices were first blanched in 0.5% calcium chloride solution at 90°C for 5 minutes. Then, they were immersed in coating solutions at 60°C for 5 minutes. After coating, the potato strips were fried at 180°C using a fryer and then various characteristics including coating percentage, oil absorption, and moisture content, texture firmness, peroxide value, acid number, color indices and sensory properties were examined. Design Expert 8.0.7.1 software was used to analyze the results and to draw the curves.
Results and Discission
The results showed that the increasing the amount of chitosan led to better coating formation in comparison with okra. The highest coverage was observed in the concentration of 1.2% chitosan and 0% okra mucilage (2.38%) and the lowest was observed in the control sample (0.11%). It was also observed that with increasing the concentration of chitosan and okra mucilage, the amount of oil absorption decreases. However, the amount of oil absorption in high concentrations of okra mucilage increased slightly. The highest oil uptake in the control sample was 20% and the lowest was observed in the sample of fried strips covered with 41% okra mucilage and 1.5% chitosan at 15.44%. The obtained model of oxidation index was not significant. The effect of okra mucilage and chitosan concentration on the texture of the samples (p <0.05) and the color indices of a* (p<0.01) and L* (p <0.05) were significant. For sensory attributes, the highest and the lowest taste score was observed for samples coated with 100% okra mucilage and 0.75% chitosan and samples coated with 18% okra mucilage and 0% chitosan respectively.
Conclusion
The aim of this project was to reduce the oil absorption of fried potato strips by coating them with chitosan and okra mucilage. Optimization to minimize the consumption of okra and chitosan mucilage showed that coating with 74% okra and 0.89% chitosan is suitable for coating potato slices. The desirability of this optimization was 71%, which is a reasonable percentage.
Research Interests:
Introduction Rice as a staple food, especially in Asian countries, can be a major source of heavy metals. Heavy metals also enter the soils where crops grow naturally and / or through human activities. Metals are absorbed and accumulated... more
Introduction
Rice as a staple food, especially in Asian countries, can be a major source of heavy metals. Heavy metals also enter the soils where crops grow naturally and / or through human activities. Metals are absorbed and accumulated in the edible parts of the plant and enter the food chain. Toxic metals, which are present in nature due to industrialization, have polluted the environment, including soil, air, water and food, and have adverse effects on human health through food chains. The Codex Organization has set maximum levels for these elements in various cereals to protect trade and health. Nitrate and nitrite are naturally present in soil, water and food. But today, foods have higher levels of nitrate and nitrite. Excessive use of nitrogen fertilizers to achieve higher yields and improper disposal of human and animal wastes may lead to nitrate accumulation in agricultural products. Very few studies have been performed on the measurement of heavy metal and nitrogen indices in replanted rice. The aim of this study was to measure the amounts of heavy metals (lead, cadmium and arsenic) and the amounts of nitrate and nitrite in first harvest rice and re-harvest rice and compare it with the standard values of the World Health Organization.
Methods and Materials
In this study, a total of 18 rice samples were prepared from three selected farms in the first and second cultivation times and the amount of nitrite, nitrate and heavy metals lead, cadmium, arsenic and mercury were evaluated.
Results and Discussion
The results showed that in all farms in the second crop the concentration of lead decreased significantly (P<0.05). The concentration of lead in all treatments of the first crop Has been more than allowed and in the second cultivation, the treatment of field number one and two, is more than allowed (P<0.05). The concentration of cadmium in all treatments is within the allowable range and in the second crop compared to the first crop of fields number one and three has a significant decrease and in field number two has increased significantly (P <0.05). The highest amount of cadmium is related to field treatments number three. The highest amount of arsenic was observed in the first crop of farm number one and it is more than the allowable limit and in other treatments the amount of arsenic was less than the allowable level and in all three farms the concentration of arsenic in the second crop was significantly reduced compared to the first crop. Regarding mercury, in fields number one and two, with the change of cultivation, the amount of mercury increased significantly and in field number three, there was a significant decrease (P <0.05). Mercury concentration is less than the allowable limit only in the second culture sample of farm number three. Nitrite and nitrate concentrations were also low in all treatments and were considered zero. Experiments showed the amount of nitrite and nitrate in all samples to be negligible and undetectable. Due to the fact that the detection limit of the method (LOQ) used to measure nitrate and nitrite is 100 ppb, the amount of nitrate and nitrite in all samples can be less than 100 ppb. The permissible level of nitrate in food products and rice grains is set at 50 mg/kg according to national standard 16596. The results of the samples showed that all 18 samples had lower amounts of nitrate than the allowable limit. Therefore, rice samples prepared from the first and second crops, their nitrate content is less than the allowable limit and have a complete degree of health.
Conclusion
According to the results obtained, all rice cultivated in the first and second crops have some arsenic, cadmium and lead, but the amount measured in some samples is less and in others, more than specified in the national standard of Iran. their consumption may be dangerous for consumers. These results also indicate that due to the stability of the field and plant type, there is a positive and significant relationship between the amount of heavy metals studied in rice and the time of cultivation, and this requires further studies on heavy metal contamination in the region. Take place. Therefore, with the conducted studies, it can be concluded that there are concerns in the consumption of rice cultivated in the city of Mazandaran province, in terms of the possibility of endangering the health of consumers.
Rice as a staple food, especially in Asian countries, can be a major source of heavy metals. Heavy metals also enter the soils where crops grow naturally and / or through human activities. Metals are absorbed and accumulated in the edible parts of the plant and enter the food chain. Toxic metals, which are present in nature due to industrialization, have polluted the environment, including soil, air, water and food, and have adverse effects on human health through food chains. The Codex Organization has set maximum levels for these elements in various cereals to protect trade and health. Nitrate and nitrite are naturally present in soil, water and food. But today, foods have higher levels of nitrate and nitrite. Excessive use of nitrogen fertilizers to achieve higher yields and improper disposal of human and animal wastes may lead to nitrate accumulation in agricultural products. Very few studies have been performed on the measurement of heavy metal and nitrogen indices in replanted rice. The aim of this study was to measure the amounts of heavy metals (lead, cadmium and arsenic) and the amounts of nitrate and nitrite in first harvest rice and re-harvest rice and compare it with the standard values of the World Health Organization.
Methods and Materials
In this study, a total of 18 rice samples were prepared from three selected farms in the first and second cultivation times and the amount of nitrite, nitrate and heavy metals lead, cadmium, arsenic and mercury were evaluated.
Results and Discussion
The results showed that in all farms in the second crop the concentration of lead decreased significantly (P<0.05). The concentration of lead in all treatments of the first crop Has been more than allowed and in the second cultivation, the treatment of field number one and two, is more than allowed (P<0.05). The concentration of cadmium in all treatments is within the allowable range and in the second crop compared to the first crop of fields number one and three has a significant decrease and in field number two has increased significantly (P <0.05). The highest amount of cadmium is related to field treatments number three. The highest amount of arsenic was observed in the first crop of farm number one and it is more than the allowable limit and in other treatments the amount of arsenic was less than the allowable level and in all three farms the concentration of arsenic in the second crop was significantly reduced compared to the first crop. Regarding mercury, in fields number one and two, with the change of cultivation, the amount of mercury increased significantly and in field number three, there was a significant decrease (P <0.05). Mercury concentration is less than the allowable limit only in the second culture sample of farm number three. Nitrite and nitrate concentrations were also low in all treatments and were considered zero. Experiments showed the amount of nitrite and nitrate in all samples to be negligible and undetectable. Due to the fact that the detection limit of the method (LOQ) used to measure nitrate and nitrite is 100 ppb, the amount of nitrate and nitrite in all samples can be less than 100 ppb. The permissible level of nitrate in food products and rice grains is set at 50 mg/kg according to national standard 16596. The results of the samples showed that all 18 samples had lower amounts of nitrate than the allowable limit. Therefore, rice samples prepared from the first and second crops, their nitrate content is less than the allowable limit and have a complete degree of health.
Conclusion
According to the results obtained, all rice cultivated in the first and second crops have some arsenic, cadmium and lead, but the amount measured in some samples is less and in others, more than specified in the national standard of Iran. their consumption may be dangerous for consumers. These results also indicate that due to the stability of the field and plant type, there is a positive and significant relationship between the amount of heavy metals studied in rice and the time of cultivation, and this requires further studies on heavy metal contamination in the region. Take place. Therefore, with the conducted studies, it can be concluded that there are concerns in the consumption of rice cultivated in the city of Mazandaran province, in terms of the possibility of endangering the health of consumers.
Research Interests:
Background and objective It was shown that contamination of agricultural pasturage with fertilizers, application of sewage and effluents in irrigation, use of pesticides and air pollution have led to the entrance of chemical... more
Background and objective
It was shown that contamination of agricultural pasturage with fertilizers, application of sewage and effluents in irrigation, use of pesticides and air pollution have led to the entrance of chemical contaminants, including metals, into plants. On the other hand, food processing is (handling, processing, transportation) considered as an important way of food contamination. Vegetable oils are essential in human dietary which is introduced as crucial sources of energy, fat soluble vitamins, and essential fatty acids. Sesamum indicum L., known as sesame seed, has been cultivated in Asian countries from ancient times as vegetable oil for cooking and seasoning ingredients. In recent years, the sesame oil has been considered due to its high antioxidant activities and nutritional properties. Due to the use of sesame seeds extracted oil in two form of ardeh oil and sesame oil, the amounts of mineral elements (phosphorus, potassium, iron, nickel, cobalt, manganese, calcium and magnesium) in sesame seeds and its extracted oils (ardeh oil and refined sesame oil) were investigated.
Materials and Methods
In order to determine the mineral concentration, refined sesame oil and ardeh oils were prepared from an imported sesame seed. In order to prepare the sesame oil, sesame seeds were put into a cold presser and the oil was extracted under low pressure. The Ardeh oil was prepared by adding water to sesame paste in the ratio of 2.2:10 and oil was separated by centrifugation. The sesame seeds and oil samples (refined sesame oil and ardeh oils) were digested by microwave digestion method in presence of 5 ml 65% nitric acid and 2 ml of hydrogen peroxide (H2O2). The digested samples were then filtered through 0.45 µm filter membrane. Then, the concentrations of phosphorus, potassium, iron, nickel, cobalt, manganese, calcium and magnesium in sesame seeds, ardeh oil and refined sesame oil were examined using Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP – OES).
Results
In the present study, the limit of detection (LOD) for each studied mineral elements were determined as nickel: 4 mg/kg, magnesium: 0.00066 mg/kg, manganese: 0.000134 mg/kg, phosphorus: 0.384 mg/kg, cobalt: 0.594 μg / kg, iron: 0.000797 mg/kg, potassium: 0.00394 mg/kg, calcium 0.005 mg/kg. According to the results, the highest amounts of mineral elements were detected in sesame seeds. The achieved results showed that the method of sesame oil extraction can reduce the mineral elements in the final sesame oils. The amounts of mineral elements in sesame seeds were estimated as P > Ca > K > Mg > Fe > Mn > Co > Ni. The pattern of mineral elements in Ardeh oil was reported as P > Fe > K > Co > Mg > Ni > Mn > Ca. The reduction pattern was reported as P > K > Fe > Ni > Co > Mn > Ca > Mg in refined sesame oil. As can be seen the order of mineral elements was changed in two oil samples and sesame seed. It was shown that except for K and Ca, all mineral elements in ardeh oil were higher than refined sesame oil. As can be seen, the refining process was effectively reduced the metals in oil samples. On the other hand, high amount of mineral elements in sesame seed in comparison to extracted oils could be attributed to lack of processing methods which are present in oil production in both methods.
Conclusion
It should be considered that presence of different metals in vegetable oils could facilitate the oil deterioration and oxidization as well as oil shelf life reduction. Since the most of the sesame lots in Iran are imported, it is necessary to monitor the amount of mineral elements.
It was shown that contamination of agricultural pasturage with fertilizers, application of sewage and effluents in irrigation, use of pesticides and air pollution have led to the entrance of chemical contaminants, including metals, into plants. On the other hand, food processing is (handling, processing, transportation) considered as an important way of food contamination. Vegetable oils are essential in human dietary which is introduced as crucial sources of energy, fat soluble vitamins, and essential fatty acids. Sesamum indicum L., known as sesame seed, has been cultivated in Asian countries from ancient times as vegetable oil for cooking and seasoning ingredients. In recent years, the sesame oil has been considered due to its high antioxidant activities and nutritional properties. Due to the use of sesame seeds extracted oil in two form of ardeh oil and sesame oil, the amounts of mineral elements (phosphorus, potassium, iron, nickel, cobalt, manganese, calcium and magnesium) in sesame seeds and its extracted oils (ardeh oil and refined sesame oil) were investigated.
Materials and Methods
In order to determine the mineral concentration, refined sesame oil and ardeh oils were prepared from an imported sesame seed. In order to prepare the sesame oil, sesame seeds were put into a cold presser and the oil was extracted under low pressure. The Ardeh oil was prepared by adding water to sesame paste in the ratio of 2.2:10 and oil was separated by centrifugation. The sesame seeds and oil samples (refined sesame oil and ardeh oils) were digested by microwave digestion method in presence of 5 ml 65% nitric acid and 2 ml of hydrogen peroxide (H2O2). The digested samples were then filtered through 0.45 µm filter membrane. Then, the concentrations of phosphorus, potassium, iron, nickel, cobalt, manganese, calcium and magnesium in sesame seeds, ardeh oil and refined sesame oil were examined using Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP – OES).
Results
In the present study, the limit of detection (LOD) for each studied mineral elements were determined as nickel: 4 mg/kg, magnesium: 0.00066 mg/kg, manganese: 0.000134 mg/kg, phosphorus: 0.384 mg/kg, cobalt: 0.594 μg / kg, iron: 0.000797 mg/kg, potassium: 0.00394 mg/kg, calcium 0.005 mg/kg. According to the results, the highest amounts of mineral elements were detected in sesame seeds. The achieved results showed that the method of sesame oil extraction can reduce the mineral elements in the final sesame oils. The amounts of mineral elements in sesame seeds were estimated as P > Ca > K > Mg > Fe > Mn > Co > Ni. The pattern of mineral elements in Ardeh oil was reported as P > Fe > K > Co > Mg > Ni > Mn > Ca. The reduction pattern was reported as P > K > Fe > Ni > Co > Mn > Ca > Mg in refined sesame oil. As can be seen the order of mineral elements was changed in two oil samples and sesame seed. It was shown that except for K and Ca, all mineral elements in ardeh oil were higher than refined sesame oil. As can be seen, the refining process was effectively reduced the metals in oil samples. On the other hand, high amount of mineral elements in sesame seed in comparison to extracted oils could be attributed to lack of processing methods which are present in oil production in both methods.
Conclusion
It should be considered that presence of different metals in vegetable oils could facilitate the oil deterioration and oxidization as well as oil shelf life reduction. Since the most of the sesame lots in Iran are imported, it is necessary to monitor the amount of mineral elements.
Research Interests:
Introduction Strawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against... more
Introduction
Strawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against post-harvest pathogens on packaging lines. However, disposal of toxic waste is a costly process and the hazardous waste causes serious environmental problems. In addition, fungal pathogens have shown a worrying trend of resistance to these fungicides, thus shortening the shelf life of products. Compounds that can be equally effective in controlling pathogens, but preventing or minimizing the waste problems will be inevitable. The large volume of internationally processed agricultural products, as well as the increasing demand for organically produced fruits, emphasizes the need to replace synthetic fungicides with safer and biodegradable alternatives. Natural plant-derived products effectively meet this criterion and have great potential to influence modern agricultural research. Catechins and other polyphenols in green tea show strong antioxidant activity. Also, the antimicrobial activity of green tea extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans has been reported. Therefore, the present study was performed to prepare the ethanolic extract of green tea and to determine the content of total phenol, total flavonoids, antioxidant activity, and its antifungal effect against Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer (causing rot in strawberry and grapes).
Materials and Methods
Fresh green tea leaves were dried at room temperature and then powdered. Then, ethanol (70%) was added to the powdered leaves (solvent to powder ratio of 10:1 v/w) and the mixture was refluxed for 120 min. The resulting mixture was filtered through a filter paper and then concentrated under vacuum and finally dried in an oven.
Total phenol content (by Folin-Ciocalteu reagent at 756 nm), total flavonoid content (spectrophotometrically at 510 nm), antioxidant activity (by DPPH and ABTS radical scavenging methods), and antifungal effect (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated.
Results and Discussion
The extract contained 175.60 mg GAE /g total phenol and 47.53 mg QE/g total flavonoids and its antioxidant activity using DPPH and ABTS free radical assays was 78.89% and 86.57%, respectively. The results of antifungal activity showed that the diameter of the growth inhibition zone increased significantly with increasing the concentration of the extract, and Botrytis cinerea and Rhizopus stolonifer were the most sensitive and resistant fungal strains to the extract, respectively. The minimum fungicidal concentrations for the strains of Botrytis cinerea and Rhizopus stolonifer were 64 and 512 mg/ml, respectively.
Conclusion
The results of the present study showed that the ethanolic extract of green tea could be considered as potential source of natural antioxidant and antifungal agents. The presence of phenolic and flavonoid compounds may be responsible for the antifungal and antioxidant effects of the extract. However, due to the fact that this study was performed with the crude extract of green tea, it is difficult to identify compounds responsible for antifungal and antioxidant activity. On this point, only the separation of the components of the extract allows the detection of antifungal and antioxidant compounds. This study provides a basis for further researches, in particular the use of these antioxidants and antifungal compounds. Green tea extract is especially suitable for products with high sensitivity to lipid oxidation and infection with molds.
Strawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against post-harvest pathogens on packaging lines. However, disposal of toxic waste is a costly process and the hazardous waste causes serious environmental problems. In addition, fungal pathogens have shown a worrying trend of resistance to these fungicides, thus shortening the shelf life of products. Compounds that can be equally effective in controlling pathogens, but preventing or minimizing the waste problems will be inevitable. The large volume of internationally processed agricultural products, as well as the increasing demand for organically produced fruits, emphasizes the need to replace synthetic fungicides with safer and biodegradable alternatives. Natural plant-derived products effectively meet this criterion and have great potential to influence modern agricultural research. Catechins and other polyphenols in green tea show strong antioxidant activity. Also, the antimicrobial activity of green tea extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans has been reported. Therefore, the present study was performed to prepare the ethanolic extract of green tea and to determine the content of total phenol, total flavonoids, antioxidant activity, and its antifungal effect against Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer (causing rot in strawberry and grapes).
Materials and Methods
Fresh green tea leaves were dried at room temperature and then powdered. Then, ethanol (70%) was added to the powdered leaves (solvent to powder ratio of 10:1 v/w) and the mixture was refluxed for 120 min. The resulting mixture was filtered through a filter paper and then concentrated under vacuum and finally dried in an oven.
Total phenol content (by Folin-Ciocalteu reagent at 756 nm), total flavonoid content (spectrophotometrically at 510 nm), antioxidant activity (by DPPH and ABTS radical scavenging methods), and antifungal effect (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated.
Results and Discussion
The extract contained 175.60 mg GAE /g total phenol and 47.53 mg QE/g total flavonoids and its antioxidant activity using DPPH and ABTS free radical assays was 78.89% and 86.57%, respectively. The results of antifungal activity showed that the diameter of the growth inhibition zone increased significantly with increasing the concentration of the extract, and Botrytis cinerea and Rhizopus stolonifer were the most sensitive and resistant fungal strains to the extract, respectively. The minimum fungicidal concentrations for the strains of Botrytis cinerea and Rhizopus stolonifer were 64 and 512 mg/ml, respectively.
Conclusion
The results of the present study showed that the ethanolic extract of green tea could be considered as potential source of natural antioxidant and antifungal agents. The presence of phenolic and flavonoid compounds may be responsible for the antifungal and antioxidant effects of the extract. However, due to the fact that this study was performed with the crude extract of green tea, it is difficult to identify compounds responsible for antifungal and antioxidant activity. On this point, only the separation of the components of the extract allows the detection of antifungal and antioxidant compounds. This study provides a basis for further researches, in particular the use of these antioxidants and antifungal compounds. Green tea extract is especially suitable for products with high sensitivity to lipid oxidation and infection with molds.
Research Interests:
Introduction Gelatin is one of the most widely used colloidal proteins, which has unique hydrocolloidal property. Gelatin is derived from collagen by changing the thermal nature. This product is widely used in food, pharmaceutical,... more
Introduction
Gelatin is one of the most widely used colloidal proteins, which has unique hydrocolloidal property. Gelatin is derived from collagen by changing the thermal nature. This product is widely used in food, pharmaceutical, biomedical, cosmetic and photography industries. Global gelatin demand for food and non-food products is increasing. Two important properties of nanoparticles are: Increasing the surface-to-volume ratio of nanoparticles causes the atoms on the surface to have a much greater effect on their properties than the atoms within the particle volume. The effects of quantum size, which is the second feature. Methods for preparing nanoparticles from natural macromolecules: In general, two major methods for making protein nanoparticles have been reported Emulsion-solvent evaporation method and sedimentation or phase separation method in aqueous medium. Numerous methods have been reported for the preparation of nanoparticles from natural macromolecules. The first method is based on emulsification and the second method is based on phase separation in aqueous medium. In the first method, due to the instability of the emulsion, it is not possible to prepare nanoparticles smaller than 500 nm with a narrow particle size distribution. Therefore, coagulation method or anti-solvent method which is based on phase separation was proposed to prepare nanoparticles from natural macromolecules.
Materials and Methods
Type B (cow) gelatin was purchased from processing company with Bloom 260-240 food and pharmaceutical Iran solvent gelatin solution of 25% aqueous acetate glutaraldehyde from Iran Neutron Company. Two-stage anti-solvent method was used to produce gelatin nanoparticles. Then, to form nanoparticles, acetone was added dropwise while stirring until the dissolved acetone begins to change color and eventually turns white, which indicates the formation of nanoparticles. Finally, glutaraldehyde solution was added for cross-linking and finally centrifuged.
Results and Discussion
The results showed that with increasing gelatin concentration, nanoparticle size and PDI increased significantly. According to the announced results, the solvent has a direct effect on the size. Therefore, the best mixing speed is determined to achieve the smallest particle size. Zeta potential is the best indicator for determining the electrical status of the particle surface and a factor for the stability of the potential of the colloidal system because it indicates the amount of charge accumulation in the immobile layer and the intensity of adsorption of opposite ions on the particle surface. If all the particles in the suspension are negatively or positively charged, the particles tend to repel each other and do not tend to accumulate. The tendency of co-particles to repel each other is directly related to the zeta potential. Fabricated gelatin nanoparticles have a stable structure, and are heat resistant. These nanoparticles are ready to be used to accept a variety of aromatic substances, compounds with high antioxidant properties, a variety of vitamins and heat-sensitive substances.
Conclusion
The results of this study showed that the optimal conditions for the production of a particle of 88.6 nm at 40 ° C, the volume of acetone consumption was 15 ml, concentration 200 mg and speed 1000 rpm, and the morphology of gelatin nanoparticles have resistant, spherical polymer structure and mesh with a smooth surface that can be clearly seen under an electron microscope.
Gelatin is one of the most widely used colloidal proteins, which has unique hydrocolloidal property. Gelatin is derived from collagen by changing the thermal nature. This product is widely used in food, pharmaceutical, biomedical, cosmetic and photography industries. Global gelatin demand for food and non-food products is increasing. Two important properties of nanoparticles are: Increasing the surface-to-volume ratio of nanoparticles causes the atoms on the surface to have a much greater effect on their properties than the atoms within the particle volume. The effects of quantum size, which is the second feature. Methods for preparing nanoparticles from natural macromolecules: In general, two major methods for making protein nanoparticles have been reported Emulsion-solvent evaporation method and sedimentation or phase separation method in aqueous medium. Numerous methods have been reported for the preparation of nanoparticles from natural macromolecules. The first method is based on emulsification and the second method is based on phase separation in aqueous medium. In the first method, due to the instability of the emulsion, it is not possible to prepare nanoparticles smaller than 500 nm with a narrow particle size distribution. Therefore, coagulation method or anti-solvent method which is based on phase separation was proposed to prepare nanoparticles from natural macromolecules.
Materials and Methods
Type B (cow) gelatin was purchased from processing company with Bloom 260-240 food and pharmaceutical Iran solvent gelatin solution of 25% aqueous acetate glutaraldehyde from Iran Neutron Company. Two-stage anti-solvent method was used to produce gelatin nanoparticles. Then, to form nanoparticles, acetone was added dropwise while stirring until the dissolved acetone begins to change color and eventually turns white, which indicates the formation of nanoparticles. Finally, glutaraldehyde solution was added for cross-linking and finally centrifuged.
Results and Discussion
The results showed that with increasing gelatin concentration, nanoparticle size and PDI increased significantly. According to the announced results, the solvent has a direct effect on the size. Therefore, the best mixing speed is determined to achieve the smallest particle size. Zeta potential is the best indicator for determining the electrical status of the particle surface and a factor for the stability of the potential of the colloidal system because it indicates the amount of charge accumulation in the immobile layer and the intensity of adsorption of opposite ions on the particle surface. If all the particles in the suspension are negatively or positively charged, the particles tend to repel each other and do not tend to accumulate. The tendency of co-particles to repel each other is directly related to the zeta potential. Fabricated gelatin nanoparticles have a stable structure, and are heat resistant. These nanoparticles are ready to be used to accept a variety of aromatic substances, compounds with high antioxidant properties, a variety of vitamins and heat-sensitive substances.
Conclusion
The results of this study showed that the optimal conditions for the production of a particle of 88.6 nm at 40 ° C, the volume of acetone consumption was 15 ml, concentration 200 mg and speed 1000 rpm, and the morphology of gelatin nanoparticles have resistant, spherical polymer structure and mesh with a smooth surface that can be clearly seen under an electron microscope.
Research Interests:
Introduction Quinoa, which is known as the mother grain,has higher protein content than common cereals and possesses a large lysine content. Quinoa is composed mainly of carbohydrates (60-75%), of which 10-13% is dietary fiber. Quinoa... more
Introduction
Quinoa, which is known as the mother grain,has higher protein content than common cereals and possesses a large lysine content. Quinoa is composed mainly of carbohydrates (60-75%), of which 10-13% is dietary fiber. Quinoa also has a slightly higher protein content (12-16%) compared with cereal grains and fat content (5-9%) that is rich in unsaturated fatty acids. Quinoa seeds contain similar or slightly higheramounts of bioactive compounds such as polyphenols (2.7-3.8 g/kg). Moreover, quinoa is gluten-free, thus providing the ability to enhance the selection of gluten-free products forconsumers with celiac disease, but this type of characteristicis challenging to development of bakery products from quinoa with desirable physicochemical properties. Processing of cereal grains and pseudo-cereals into products that deliver a nutritive valueto consumers represents a considerable opportunity for large scale food processing. There havebeen some reported studies on roasting, extrusion, steam pre-conditioning and pearling of quinoafor further uses. Extrusion cooking is a promising technology for improvement of functional properties of quinoa flour. The Evaluation of physicochemical properties and microstructure of Expanded quinoa as affected by extrusion conditions was the main goal of this project.
Material and Methods
In this study, a parallel twin-screw extruder (Jinan Saxin, China) with die diameter of 3 mm was applied. The effects of extrusion process parameters including feed moisture content (14 and 16%) and die temperature (130, 150 and 170 °C) on final moisture content, bulk density, water absorption index (WAI), color parametersL* (lightness), a*(redness), b*(yellowness), hardness, and microstructure of Expanded quinoa were studied. Extrusion was carried out using a co-rotating twin screw extruder with L/D ratio of 10:1 and die diameter of 4 mm. The feed rate of flour and the screw speed were set at 40 kg/h and 200 rpm, respectively. The physicochemical properties were measured using standard methods. The hardness measurement was performed by a texture analyzer. The cylinder steel probe (2 mm diameter) was set to move at a speed of 1 mm/s The samples were punctured by the probe to a distance of 10 mm . The color parameters of the samples were determined by the Hunterlab machine. The morphology of samples was assessed using a scanning electron microscopy (SEM).
Results and Discussion
A comprehensive study on impacts of extrusion processing conditions on quinoa flour was conducted. The effect of process variables on the physicochemical attributes of the extrudates was observed. the expanded quinoa with higher feed moisture content had greater moisture and those extruded at higher die temperatures showed lower moisture content (p<0.05). Moisture can reduce the shear force as a plasticizer and increase the amount of moisture absorption of the product. While increasing the die temperature, the effect of shear force on starch dextrification increases and reduces moisture absorption (p<0.05). WAI was significantly influenced by extrusion variables. In fact, feed moisture content and die temperature both positively changed the WAI of quinoa flour so that all extruded samples had significantly higher WAI than the untreated sample (p<0.05). Moreover, the sample with the higher feed moisture content (24%) treated at the highest extrusion temperature (170 °C) showed the largest and lowest water absorption and Hardness respectively (p<0.05). Another important feature of expanded quinoa is the lightness index, the results revealed that extrusion cooking caused a reduction in L* and enhancements in a* and b*. While changes in color parameters were more pronounced at more severe die temperature, higher feed moisture content counteracted the effects of cooking temperature on the color of the products. As expected from changes in the abovementioned color parameters, the sample with lower feed moisture content (16%) treated at the highest extrusion temperature (170 °C) experienced the greatest color change (ΔE). The texture profile analysis (TPA) indicated that higher feed moisture content yielded extrudates with harder texture whereas, extrusion at higher temperature resulted in lower hardness. The scanning electron micrographs showed that the native quinoa flour encompassed both small- and large-sized starch granules while the extruded sample mainly consisted of disaggregated particles. Furthermore, extrusion cooking of samples with higher feed moisture content caused formation of more uniform starch aggregates with smoother surfaces.
Quinoa, which is known as the mother grain,has higher protein content than common cereals and possesses a large lysine content. Quinoa is composed mainly of carbohydrates (60-75%), of which 10-13% is dietary fiber. Quinoa also has a slightly higher protein content (12-16%) compared with cereal grains and fat content (5-9%) that is rich in unsaturated fatty acids. Quinoa seeds contain similar or slightly higheramounts of bioactive compounds such as polyphenols (2.7-3.8 g/kg). Moreover, quinoa is gluten-free, thus providing the ability to enhance the selection of gluten-free products forconsumers with celiac disease, but this type of characteristicis challenging to development of bakery products from quinoa with desirable physicochemical properties. Processing of cereal grains and pseudo-cereals into products that deliver a nutritive valueto consumers represents a considerable opportunity for large scale food processing. There havebeen some reported studies on roasting, extrusion, steam pre-conditioning and pearling of quinoafor further uses. Extrusion cooking is a promising technology for improvement of functional properties of quinoa flour. The Evaluation of physicochemical properties and microstructure of Expanded quinoa as affected by extrusion conditions was the main goal of this project.
Material and Methods
In this study, a parallel twin-screw extruder (Jinan Saxin, China) with die diameter of 3 mm was applied. The effects of extrusion process parameters including feed moisture content (14 and 16%) and die temperature (130, 150 and 170 °C) on final moisture content, bulk density, water absorption index (WAI), color parametersL* (lightness), a*(redness), b*(yellowness), hardness, and microstructure of Expanded quinoa were studied. Extrusion was carried out using a co-rotating twin screw extruder with L/D ratio of 10:1 and die diameter of 4 mm. The feed rate of flour and the screw speed were set at 40 kg/h and 200 rpm, respectively. The physicochemical properties were measured using standard methods. The hardness measurement was performed by a texture analyzer. The cylinder steel probe (2 mm diameter) was set to move at a speed of 1 mm/s The samples were punctured by the probe to a distance of 10 mm . The color parameters of the samples were determined by the Hunterlab machine. The morphology of samples was assessed using a scanning electron microscopy (SEM).
Results and Discussion
A comprehensive study on impacts of extrusion processing conditions on quinoa flour was conducted. The effect of process variables on the physicochemical attributes of the extrudates was observed. the expanded quinoa with higher feed moisture content had greater moisture and those extruded at higher die temperatures showed lower moisture content (p<0.05). Moisture can reduce the shear force as a plasticizer and increase the amount of moisture absorption of the product. While increasing the die temperature, the effect of shear force on starch dextrification increases and reduces moisture absorption (p<0.05). WAI was significantly influenced by extrusion variables. In fact, feed moisture content and die temperature both positively changed the WAI of quinoa flour so that all extruded samples had significantly higher WAI than the untreated sample (p<0.05). Moreover, the sample with the higher feed moisture content (24%) treated at the highest extrusion temperature (170 °C) showed the largest and lowest water absorption and Hardness respectively (p<0.05). Another important feature of expanded quinoa is the lightness index, the results revealed that extrusion cooking caused a reduction in L* and enhancements in a* and b*. While changes in color parameters were more pronounced at more severe die temperature, higher feed moisture content counteracted the effects of cooking temperature on the color of the products. As expected from changes in the abovementioned color parameters, the sample with lower feed moisture content (16%) treated at the highest extrusion temperature (170 °C) experienced the greatest color change (ΔE). The texture profile analysis (TPA) indicated that higher feed moisture content yielded extrudates with harder texture whereas, extrusion at higher temperature resulted in lower hardness. The scanning electron micrographs showed that the native quinoa flour encompassed both small- and large-sized starch granules while the extruded sample mainly consisted of disaggregated particles. Furthermore, extrusion cooking of samples with higher feed moisture content caused formation of more uniform starch aggregates with smoother surfaces.
Research Interests:
Introduction Bran-enriched bread is a source of dietary fibers and other nutritional compounds; However, wheat bran also contains phytic acid, asparagine, a high ratio of insoluble to soluble fiber, insoluble arabinoxylans, and... more
Introduction
Bran-enriched bread is a source of dietary fibers and other nutritional compounds; However, wheat bran also contains phytic acid, asparagine, a high ratio of insoluble to soluble fiber, insoluble arabinoxylans, and glutathione that cause nutritional and technological problems in the product. Therefore, to produce bran-enriched bread, it is necessary to use pre-processed wheat bran. Despite the modifications made in wheat bran to improve its nutritional and functional properties, wheat bran-rich cereal products have a dark color, rough texture, and small loaf volume. To improve the quality of bran-enriched bread, common additives in the bakery industry such as enzymes, alcoholic sugars, emulsifiers can be used. Xylanase is one of the important classes of hemicellulase enzymes that delays the aggregation of amylose chains, and consequently, bread staling. Moreover, the xylanase enzyme increases the loaf volume by converting water-insoluble arabinoxylans into soluble ones. SSL emulsifier can interact with gliadin protein and prevent its participation in crosslinking bonds, which softens the bread crumbs. Polyols can reduce water activity and improve the softness of bread. Sorbitol is commonly used in starch-based foods to improve their quality by modifying starch gelatinization and retrogradation. So far, no article has been presented on the simultaneous effect of enzyme, alcoholic sugar, and emulsifier improvers on bread enriched with processed wheat bran. In addition, the amount and composition of improvers used in combination with each other can cause various effects on different properties of bread. This study aims to improve the technological, physicochemical, and finally stalling of optimal bread enriched with 15% of pre-processed wheat bran while benefiting from the nutritional properties of wheat bran.
Materials and Methods
In this study, the effect of sodium stearoyl-2-lactylate emulsifier (0-0.8%), xylanase enzyme (0-0.05%), and sorbitol sugar alcohol (0-6%) as improving agents on The physicochemical and technological parameters of bread enriched with 15% pre-processed wheat bran were investigated based on the response surface method in the form of a rotatable central composite design. After that, design-expert software determined the optimum percentage of improvers to achieve the minimum amount of firmness and cohesiveness of bread and the maximum amount of specific volume, moisture of bread crumbs, lightness of bread crust, and solidity of bread pore structure. Finally, optimal and control samples were compared using the Differential Scanning Calorimetry and Scanning Electron Microscopic experiments.
Results and Discussion
The experiments showed the bread's firmness under the influence of SSL emulsifier and sorbitol alcoholic sugar and chewiness, by adding SSL emulsifier and xylanase enzyme decreased significantly. All three improvers caused a significant increase in the specific volume of bread. The pore characteristics of bread crumbs, such as solidity and circularity, were significantly improved by adding an SSL emulsifier, and roundness was considerably enhanced by adding sorbitol alcohol. The brightness of bread crust was also increased significantly by the SSL emulsifier and xylanase enzyme. In addition, the Xylanase enzyme improved the moisture content of bread by substantially increasing the moisture content of bread crumbs, and alcoholic sugar and SSL emulsifier with a significant reduction in crust moisture. Moreover, the chewiness of bread on the first day after baking, specific volume, moisture of bread crust on the third day after baking, and the solidity of bread crumbs were significantly improved due to the interaction of SSL emulsifier and sorbitol alcohol. Also, the interaction of the xylanase enzyme and SSL emulsifier improved the specific volume, moisture of the bread crumbs on the first day after baking, the lightness of the bread crust, the pore area fraction, and the circularity of the bread crumbs. Finally, the optimal formula was obtained, including 0.563% of SSL emulsifier, 0.040% of xylanase enzyme, and 2.356% of alcoholic sugar sorbitol. The results showed a significant decrease in enthalpy and an increase in the initial gelatinization temperature in the optimal sample compared to the control ones. Also, a weaker gluten network, more swelling, and amounts of starch granules in the microstructure of sample bread were observed.
Conclusion
In conclusion, SSL emulsifier by interaction with amylose and amylopectin in starch granules, sorbitol alcohol via interacting with water molecules surrounding starch chains or by bonding between starch chains in amorous regions, and xylanase enzyme through reducing rate of crystallization can reduce the gelatinization of starch granules, enthalpy, and finally the retrogradation process of amylopectin and stalling rate of bread with their synergic effects. In this research, we formulate the wheat bran-enriched bread that not only benefits from the nutritional features of wheat bran but also preserves the quality characteristics of bread.
Bran-enriched bread is a source of dietary fibers and other nutritional compounds; However, wheat bran also contains phytic acid, asparagine, a high ratio of insoluble to soluble fiber, insoluble arabinoxylans, and glutathione that cause nutritional and technological problems in the product. Therefore, to produce bran-enriched bread, it is necessary to use pre-processed wheat bran. Despite the modifications made in wheat bran to improve its nutritional and functional properties, wheat bran-rich cereal products have a dark color, rough texture, and small loaf volume. To improve the quality of bran-enriched bread, common additives in the bakery industry such as enzymes, alcoholic sugars, emulsifiers can be used. Xylanase is one of the important classes of hemicellulase enzymes that delays the aggregation of amylose chains, and consequently, bread staling. Moreover, the xylanase enzyme increases the loaf volume by converting water-insoluble arabinoxylans into soluble ones. SSL emulsifier can interact with gliadin protein and prevent its participation in crosslinking bonds, which softens the bread crumbs. Polyols can reduce water activity and improve the softness of bread. Sorbitol is commonly used in starch-based foods to improve their quality by modifying starch gelatinization and retrogradation. So far, no article has been presented on the simultaneous effect of enzyme, alcoholic sugar, and emulsifier improvers on bread enriched with processed wheat bran. In addition, the amount and composition of improvers used in combination with each other can cause various effects on different properties of bread. This study aims to improve the technological, physicochemical, and finally stalling of optimal bread enriched with 15% of pre-processed wheat bran while benefiting from the nutritional properties of wheat bran.
Materials and Methods
In this study, the effect of sodium stearoyl-2-lactylate emulsifier (0-0.8%), xylanase enzyme (0-0.05%), and sorbitol sugar alcohol (0-6%) as improving agents on The physicochemical and technological parameters of bread enriched with 15% pre-processed wheat bran were investigated based on the response surface method in the form of a rotatable central composite design. After that, design-expert software determined the optimum percentage of improvers to achieve the minimum amount of firmness and cohesiveness of bread and the maximum amount of specific volume, moisture of bread crumbs, lightness of bread crust, and solidity of bread pore structure. Finally, optimal and control samples were compared using the Differential Scanning Calorimetry and Scanning Electron Microscopic experiments.
Results and Discussion
The experiments showed the bread's firmness under the influence of SSL emulsifier and sorbitol alcoholic sugar and chewiness, by adding SSL emulsifier and xylanase enzyme decreased significantly. All three improvers caused a significant increase in the specific volume of bread. The pore characteristics of bread crumbs, such as solidity and circularity, were significantly improved by adding an SSL emulsifier, and roundness was considerably enhanced by adding sorbitol alcohol. The brightness of bread crust was also increased significantly by the SSL emulsifier and xylanase enzyme. In addition, the Xylanase enzyme improved the moisture content of bread by substantially increasing the moisture content of bread crumbs, and alcoholic sugar and SSL emulsifier with a significant reduction in crust moisture. Moreover, the chewiness of bread on the first day after baking, specific volume, moisture of bread crust on the third day after baking, and the solidity of bread crumbs were significantly improved due to the interaction of SSL emulsifier and sorbitol alcohol. Also, the interaction of the xylanase enzyme and SSL emulsifier improved the specific volume, moisture of the bread crumbs on the first day after baking, the lightness of the bread crust, the pore area fraction, and the circularity of the bread crumbs. Finally, the optimal formula was obtained, including 0.563% of SSL emulsifier, 0.040% of xylanase enzyme, and 2.356% of alcoholic sugar sorbitol. The results showed a significant decrease in enthalpy and an increase in the initial gelatinization temperature in the optimal sample compared to the control ones. Also, a weaker gluten network, more swelling, and amounts of starch granules in the microstructure of sample bread were observed.
Conclusion
In conclusion, SSL emulsifier by interaction with amylose and amylopectin in starch granules, sorbitol alcohol via interacting with water molecules surrounding starch chains or by bonding between starch chains in amorous regions, and xylanase enzyme through reducing rate of crystallization can reduce the gelatinization of starch granules, enthalpy, and finally the retrogradation process of amylopectin and stalling rate of bread with their synergic effects. In this research, we formulate the wheat bran-enriched bread that not only benefits from the nutritional features of wheat bran but also preserves the quality characteristics of bread.
Research Interests:
Introduction Oxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against... more
Introduction
Oxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, the use of natural antimicrobials and antioxidants has been increased. Natural antimicrobial compounds have the potential to control microbial contamination and reduce the use of antibiotics. Plant essential oils are natural compounds with the potential to be used as active ingredients in the food, pharmaceutical, and cosmetic industries. Various studies have shown that essential oils have antifungal, antibacterial, antiviral, and antioxidant activity. The essential oils are considered as superb preservatives with various biological functions. Essential oils are generally recognized as safe product (GRAS) which can be used as an alternative to synthetic additives.
Grapefruit (Citrus paradisi) peel and fruit contain active ingredients such as acids, flavonoids, vitamin C, and potassium, and its essential oil is composed of terpenic hydrocarbons, such as citral, limonene, citronelal, and geraniol. Although plant essential oils have antimicrobial and antioxidant properties, one of the main problems of these natural compounds is their high volatility and instability. In this context, nanoemulsion formulations are frequently used to increase the stability and efficiency of these biologically active compounds. This study is therefore aimed to nanoemulsifying the grapefruit essential oil and evaluate its antioxidant and antimicrobial properties.
Materials and Methods
β-carotene, linoleic acid, ABTS (2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and DPPH (2,2-diphenly-1-picrylhydrazyl) were purchased from Sigma-Aldrich Co. (USA). Mueller Hinton Broth (MHB) and Mueller Hinton Agar (MHA) were supplied from Merck Co. (Darmstadt, Germany). Grapefruit peel was dried at ambient temperature and then powdered. The obtained powder was then transferred to a Clevenger device containing 750 ml of distilled water to perform the distillation extraction (3 h). The resulting grapefruit essential oil was stored at 4 °C until use. Grapefruit essential oil was prepared using the hydrodistillation method, and then nanoemulsified. The antioxidant activity of the nanoemulsified essential oil was investigated by DPPH and ABTS radical scavenging activity and beta-carotene/linoleic bleaching test. The nanoemulsified essential oil or methanolic (control) was mixed with DPPH solution and the mixture was then stored at ambient temperature for 30 min, in a dark place. The control sample was prepared by methanol. The absorbance of the samples was measured at 517 nm. To determine the ABTS-RS activity, the nanoemulsified essential oil was briefly charged with methanolic ABTS radical cation solution and the resulting mixture was left at room temperature for 30 min. Afterward, the absorbance was read at 734 nm. A spectrophotometric method was applied to monitor β-carotene/linoleate solution bleaching in the presence of the nanoemulsified essential oil. To do this, the absorbance of the solution was recorded at 490 nm after 120 min against the control sample at time zero and after 120 min. Antibacterial effect of the grapefruit essential oil nanoemulsion was also evaluated against Escherichia coli ATCC 25922, Salmonella typhi ATCC 6539, Pseudomonas aeruginosa ATCC 27853, Listeria innocua ATCC 33090, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 23857, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 12228, based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration.
Results and Discussions
The results showed that the nanoemulsion of grapefruit essential oil had a remarkable antioxidant effect of 42.27 mg/ml, 33.27 mg/ml and 54.54%, respectively, based on DPPH, ABTS, and beta-carotene-linoleic acid bleaching tests. According to disk diffusion agar and well diffusion agar results, the lowest inhibition zone was related to E. coli and the highest inhibition zone was observed in L. innocua. The minimum inhibitory concentration for L. innocua and S. aureus (the most sensitive bacteria) was 25 mg/ml, and E. coli, S. typhi, and P. aeruginosa had the highest inhibitory concentration. Also, the lowest bactericidal concentration was related to L. innocua and S. aureus bacteria and the highest concentration was observed for E. coli, S. typhi and P. aeruginosa. The nanoemulsified essential oil generally exhibited greater antibacterial activity against Gram-positive species. This could be mainly due to the difference in the cell wall composition of Gram-positive bacteria in comparison to Gram-negative; Gram-positive bacteria have a thicker mucopeptide layer in their cell wall, while Gram-negative bacteria have only a thin layer of mucopeptide and the wall structure is mainly composed of lipoprotein and lipopolysaccharide, thereby leading to a higher resistant to antibacterial agents According to the results, grapefruit essential oil nanoemulsion can be used as a natural antioxidant and antimicrobial agent to control oxidation reactions and the growth of spoilage and pathogenic microorganisms.
Oxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, the use of natural antimicrobials and antioxidants has been increased. Natural antimicrobial compounds have the potential to control microbial contamination and reduce the use of antibiotics. Plant essential oils are natural compounds with the potential to be used as active ingredients in the food, pharmaceutical, and cosmetic industries. Various studies have shown that essential oils have antifungal, antibacterial, antiviral, and antioxidant activity. The essential oils are considered as superb preservatives with various biological functions. Essential oils are generally recognized as safe product (GRAS) which can be used as an alternative to synthetic additives.
Grapefruit (Citrus paradisi) peel and fruit contain active ingredients such as acids, flavonoids, vitamin C, and potassium, and its essential oil is composed of terpenic hydrocarbons, such as citral, limonene, citronelal, and geraniol. Although plant essential oils have antimicrobial and antioxidant properties, one of the main problems of these natural compounds is their high volatility and instability. In this context, nanoemulsion formulations are frequently used to increase the stability and efficiency of these biologically active compounds. This study is therefore aimed to nanoemulsifying the grapefruit essential oil and evaluate its antioxidant and antimicrobial properties.
Materials and Methods
β-carotene, linoleic acid, ABTS (2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and DPPH (2,2-diphenly-1-picrylhydrazyl) were purchased from Sigma-Aldrich Co. (USA). Mueller Hinton Broth (MHB) and Mueller Hinton Agar (MHA) were supplied from Merck Co. (Darmstadt, Germany). Grapefruit peel was dried at ambient temperature and then powdered. The obtained powder was then transferred to a Clevenger device containing 750 ml of distilled water to perform the distillation extraction (3 h). The resulting grapefruit essential oil was stored at 4 °C until use. Grapefruit essential oil was prepared using the hydrodistillation method, and then nanoemulsified. The antioxidant activity of the nanoemulsified essential oil was investigated by DPPH and ABTS radical scavenging activity and beta-carotene/linoleic bleaching test. The nanoemulsified essential oil or methanolic (control) was mixed with DPPH solution and the mixture was then stored at ambient temperature for 30 min, in a dark place. The control sample was prepared by methanol. The absorbance of the samples was measured at 517 nm. To determine the ABTS-RS activity, the nanoemulsified essential oil was briefly charged with methanolic ABTS radical cation solution and the resulting mixture was left at room temperature for 30 min. Afterward, the absorbance was read at 734 nm. A spectrophotometric method was applied to monitor β-carotene/linoleate solution bleaching in the presence of the nanoemulsified essential oil. To do this, the absorbance of the solution was recorded at 490 nm after 120 min against the control sample at time zero and after 120 min. Antibacterial effect of the grapefruit essential oil nanoemulsion was also evaluated against Escherichia coli ATCC 25922, Salmonella typhi ATCC 6539, Pseudomonas aeruginosa ATCC 27853, Listeria innocua ATCC 33090, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 23857, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 12228, based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration.
Results and Discussions
The results showed that the nanoemulsion of grapefruit essential oil had a remarkable antioxidant effect of 42.27 mg/ml, 33.27 mg/ml and 54.54%, respectively, based on DPPH, ABTS, and beta-carotene-linoleic acid bleaching tests. According to disk diffusion agar and well diffusion agar results, the lowest inhibition zone was related to E. coli and the highest inhibition zone was observed in L. innocua. The minimum inhibitory concentration for L. innocua and S. aureus (the most sensitive bacteria) was 25 mg/ml, and E. coli, S. typhi, and P. aeruginosa had the highest inhibitory concentration. Also, the lowest bactericidal concentration was related to L. innocua and S. aureus bacteria and the highest concentration was observed for E. coli, S. typhi and P. aeruginosa. The nanoemulsified essential oil generally exhibited greater antibacterial activity against Gram-positive species. This could be mainly due to the difference in the cell wall composition of Gram-positive bacteria in comparison to Gram-negative; Gram-positive bacteria have a thicker mucopeptide layer in their cell wall, while Gram-negative bacteria have only a thin layer of mucopeptide and the wall structure is mainly composed of lipoprotein and lipopolysaccharide, thereby leading to a higher resistant to antibacterial agents According to the results, grapefruit essential oil nanoemulsion can be used as a natural antioxidant and antimicrobial agent to control oxidation reactions and the growth of spoilage and pathogenic microorganisms.
Research Interests:
Introduction It is believed that edible oils and fats with high levels of unsaturated fatty acids are susceptible to oxidation. Soybean oil as one of the four important edible oils has high content of polyunsaturated fatty acids and so... more
Introduction
It is believed that edible oils and fats with high levels of unsaturated fatty acids are susceptible to oxidation. Soybean oil as one of the four important edible oils has high content of polyunsaturated fatty acids and so prone to oxidation. Generally, lipid oxidation leads to deterioration of nutritional quality and organoleptic properties of edible oils and fats as well as accelerate the development or progression of cancer, mutagenesis, carcinogenesis, aging and cardiovascular diseases through the formation of free radicals. Therefore, edible oils and fats fortification with antioxidant compounds in order to protect them against oxidation is essential. In recent years, numerous studies were carried out on exploration of natural and safe antioxidant compounds due to the consumers concerns about potential health risk of synthetic antioxidants, such as butylatedhydroxyanisole (BHA), butylatedhydroxytolene (BHT), tert-butylhydroquinone (TBHQ) and propylgallate (PG). In this regard, TBHQ as the most powerful synthetic antioxidant is prohibited as food additive in Japan, Canada and Europe. Ferulago angulata Boiss which called chavir or chavil belongs to the family of Apiacea consisting of 35–40 species that 8 species grow in Iran. It was reported that Ferulago species are used in folk medicine for their tonic, digestive, sedative, aphrodisiac properties from ancient times. Therefore, in the current study, the oxidation development of soybean oil enriched with F. angulata essential oil (EO) during accelerated storage was investigated.
Materials and Methods
EO from freeze dried aerial parts of F. angulata was extracted through hydrodistillation using Clevenger type apparatus. Gas chromatography-mass spectrometry (GC-MS) was used to identify main components of the EO. Total phenolic and flavonoid content of the EO were assessed using Folin–Ciocalteu and aluminium chloride colorimetry methods, respectively. Antioxidant activity of EO was measured through 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and reducing power (RP) tests. Then, the EO of F. angulata at three concentrations, i.e. 200 ppm (SO-200), 400 ppm (SO-400), and SO-Mixture (100 ppm TBHQ + 100 ppm EO) were added to soybean oil. The synthetic antioxidant of TBHQ at the concentration of 200 ppm was added as control. The effect of EO from freeze dried aerial parts of F. angulata on oxidative stability of soybean oil stored under accelerated conditions at 65 ºC for 24 days was evaluated through acidity, peroxide (PV), p-anisidine (p-An) and TOTOX values.
Results and Discussion
Extraction yield, total phenolic and flavonoid contents of EO of F. angulata were 2.5% v/w, 188 mg GAE/g and 70.90 mg QE/g respectively. Furthermore, DPPH free radical scavenging activity and RP were 55.45-13.21% and 3.61-2.72 in the concentration range of 1.6-4.6 mg/ml of EO, respectively. Based on GC-MS analysis, the EO contains 41 natural compounds, representing 96.97% of the total EO. F. angulata EO could effectively reduce the acidity, PV and p-An values. For control sample, the maximum values of acidity, PV peroxide, p-An and TOTOX were 1.52 mg KOH/g, 10.60 meq O2/kg, 12.48 and 33.68 respectively after 24 days under accelerated conditions. While these values were 0.085 mg KOH/g, 4.5 meq O2/kg, 9.16 and 18.16 respectively for the soybean oil containing the lowest concentration of EO of F. angulata.
Conclusion
The results confirmed the instability of soybean oil during storage as well as the ability of EO from F. angulata for soybean oil protection against oxidation. As a result, EO from aerial parts of F. angulata could be suggested as a natural and effective antioxidant to be used instead of TBHQ as a synthetic antioxidant for soybean oil stabilization.
It is believed that edible oils and fats with high levels of unsaturated fatty acids are susceptible to oxidation. Soybean oil as one of the four important edible oils has high content of polyunsaturated fatty acids and so prone to oxidation. Generally, lipid oxidation leads to deterioration of nutritional quality and organoleptic properties of edible oils and fats as well as accelerate the development or progression of cancer, mutagenesis, carcinogenesis, aging and cardiovascular diseases through the formation of free radicals. Therefore, edible oils and fats fortification with antioxidant compounds in order to protect them against oxidation is essential. In recent years, numerous studies were carried out on exploration of natural and safe antioxidant compounds due to the consumers concerns about potential health risk of synthetic antioxidants, such as butylatedhydroxyanisole (BHA), butylatedhydroxytolene (BHT), tert-butylhydroquinone (TBHQ) and propylgallate (PG). In this regard, TBHQ as the most powerful synthetic antioxidant is prohibited as food additive in Japan, Canada and Europe. Ferulago angulata Boiss which called chavir or chavil belongs to the family of Apiacea consisting of 35–40 species that 8 species grow in Iran. It was reported that Ferulago species are used in folk medicine for their tonic, digestive, sedative, aphrodisiac properties from ancient times. Therefore, in the current study, the oxidation development of soybean oil enriched with F. angulata essential oil (EO) during accelerated storage was investigated.
Materials and Methods
EO from freeze dried aerial parts of F. angulata was extracted through hydrodistillation using Clevenger type apparatus. Gas chromatography-mass spectrometry (GC-MS) was used to identify main components of the EO. Total phenolic and flavonoid content of the EO were assessed using Folin–Ciocalteu and aluminium chloride colorimetry methods, respectively. Antioxidant activity of EO was measured through 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and reducing power (RP) tests. Then, the EO of F. angulata at three concentrations, i.e. 200 ppm (SO-200), 400 ppm (SO-400), and SO-Mixture (100 ppm TBHQ + 100 ppm EO) were added to soybean oil. The synthetic antioxidant of TBHQ at the concentration of 200 ppm was added as control. The effect of EO from freeze dried aerial parts of F. angulata on oxidative stability of soybean oil stored under accelerated conditions at 65 ºC for 24 days was evaluated through acidity, peroxide (PV), p-anisidine (p-An) and TOTOX values.
Results and Discussion
Extraction yield, total phenolic and flavonoid contents of EO of F. angulata were 2.5% v/w, 188 mg GAE/g and 70.90 mg QE/g respectively. Furthermore, DPPH free radical scavenging activity and RP were 55.45-13.21% and 3.61-2.72 in the concentration range of 1.6-4.6 mg/ml of EO, respectively. Based on GC-MS analysis, the EO contains 41 natural compounds, representing 96.97% of the total EO. F. angulata EO could effectively reduce the acidity, PV and p-An values. For control sample, the maximum values of acidity, PV peroxide, p-An and TOTOX were 1.52 mg KOH/g, 10.60 meq O2/kg, 12.48 and 33.68 respectively after 24 days under accelerated conditions. While these values were 0.085 mg KOH/g, 4.5 meq O2/kg, 9.16 and 18.16 respectively for the soybean oil containing the lowest concentration of EO of F. angulata.
Conclusion
The results confirmed the instability of soybean oil during storage as well as the ability of EO from F. angulata for soybean oil protection against oxidation. As a result, EO from aerial parts of F. angulata could be suggested as a natural and effective antioxidant to be used instead of TBHQ as a synthetic antioxidant for soybean oil stabilization.
Research Interests:
The use of edible coatings has been considered as an effective solution to improve the shelf life and quality of fruits. In this research, increase in the shelf life of citrus fruits (Citrus aurantifolia cv. Mexican lime) coated with... more
The use of edible coatings has been considered as an effective solution to improve the shelf life and quality of fruits. In this research, increase in the shelf life of citrus fruits (Citrus aurantifolia cv. Mexican lime) coated with Persian gum and pomegranate seed oil was investigated. Different treatments of lemon fruit coated with Persian gum and pomegranate seed oil with concentrations (zero (control), 0.5% and 1% gum, combination of 0.5% and 1% gum and pomegranate seed oil, 0.05% and pomegranate seed oil 0.05 percent) were prepared and after 24 days of storage at ambient temperature (20 ± 2 °C and relative humidity of 50-60 percent) were statistically evaluated in the form of a completely random design with three replications. The results of this research showed that the treatments used had an effective role in controlling the weight loss of fruit during storage. Thus, the lowest percentage of weight loss was observed in the pomegranate seed oil treatment. Except pomegranate seed oil treatment, other treatments showed less TSS than the control. In most of the treatments, the content of phenol, flavonoid and antioxidant was at a higher level than the control. The average comparison results showed that the fruits coated with 1% gum (85.36 units/ml) showed significantly more peroxidase activity than the control (60.35 U/ml). Persian gum edible coating 1% and 0.5% as well as Persian gum 1% in combination with pomegranate seed oil significantly controlled the activity of polyphenol oxidase enzyme. The treated samples showed less yellowness (b*) than the control. In general, the best marketability was observed in fruits coated with 1% gum. Therefore, it is recommended to use this coating to preserve the freshness and quality of the Mexican lime fruit during storage in the environment.
Research Interests:
The essential oils usually have a good effect against undesirable microorganisms; therefore, they can be utilized as natural antimicrobial agents in food or their packaging. In this research, the antimicrobial attributes of two essential... more
The essential oils usually have a good effect against undesirable microorganisms; therefore, they can be utilized as natural antimicrobial agents in food or their packaging. In this research, the antimicrobial attributes of two essential oils (Oliveria decumbens and Pistacia atlantica gum), have been investigated before and after thermal process (200C - 10 minutes) against bacterial and mold spoilage in bread. Also, the compounds of essential oils were detected by gas chromatography-mass spectrometry. The main compounds of the essential oil of O. decumbens were carvacrol, thymol, and elemicin before and after thermal treatment. In the case of P. atlantica gum, only one prominent peak was observed in the chromatogram, which was related to the α-pinene. For both essential oils, the MIC and MFC against Aspergillus niger were 4000 and 8000 μL/ml, respectively. In comparison, the antimicrobial effect of both essential oils against Bacillus subtilis was higher than the mold. The amount of MIC and MBC were 125 and 250 μL/ml for Oliveria decumbens and 62.5 and 125 μL/ml for Pistacia atlantica gum, respectively. The results showed that these two essential oils have a promising effect against the main microorganisms of bread spoilage. The thermal process did not significantly affect the antimicrobial activity of Pistacia atlantica gum essential oil against A. niger but significantly decreased the antimicrobial activity against B. subtilis, while in the case of antimicrobial activity of Oliveria decumbens essential oil, the results were the opposite. Considering the fact that the most spoilage agents of the bread are molds so the use of Pistacia atlantica gum essential oil is recommended as natural preservatives in products that tolerate high heat treatment, such as bread and bakery products.
Research Interests:
Iranian men are at risk of developing gastrointestinal cancer caused by H. pylori. It is very imperative to find effective methods to control this bacterium as there are currently no very effective treatments for it. Honey has been shown... more
Iranian men are at risk of developing gastrointestinal cancer caused by H. pylori. It is very imperative to find effective methods to control this bacterium as there are currently no very effective treatments for it. Honey has been shown to have antimicrobial properties against various pathogens. This study analyzed 15 honey samples from A. florea bees, collected from different floral and geographical origins, for their antimicrobial efficacy against H. pylori. Using atomic absorption measurements, the honey samples were also tested for their phenolic and flavonoid content, protein concentration, and mineral content. Antioxidant activity was determined using the FRAP, DPPH, and ABTS methods. The antibacterial activity of honey samples was investigated both in-vitro and in-vivo in the gastrointestinal tract of mice. Statistical analysis revealed a significant positive correlation between antioxidant activity and antibacterial activity. All honey samples showed antimicrobial activity in-vitro, among which jujube honey from Bushehr exhibiting the highest activity. Differences in antioxidant and antimicrobial activities were likely due to the flora of the plants and the geographic region from which the honey was harvested. Based on these results, A. florea honey may be used in the prevention and treatment of H. pylori-associated infections and inflammation of the gastrointestinal tract. This feature can be applied to the control of Helicobacter pylori along with other available measures.
Research Interests:
Collagen has diverse general and biomedical applications and its important role in the future of society have made it a key biopolymer for human health and well-being. Therefore, the present study was conducted with the objectives of... more
Collagen has diverse general and biomedical applications and its important role in the future of society have made it a key biopolymer for human health and well-being. Therefore, the present study was conducted with the objectives of extracting collagen from the skin of farmed carp, determining the quality characteristics of collagen, and comparing them. Collagen was extracted from the skin of carp fishes by acidic enzymatic method using 0.5 M acetic acid and pepsin in 48 hours. Collagen treatments (5 treatments) included collagen prepared from the skin of common species, grass carp, bighead, silver, and cow (control). Collagen treatments were not capable of hemolysis and did not show toxic effects on human fibroblast cells. Heavy metals (0.01-0.18 ppm) in collagen extracted from cultured carp species were within the standard range. The color (brightness) of experimental collagen (92.74-93.68) and control (92.38) showed no significant difference (p>0.05). Amino acids cysteine and tryptophan were not observed in collagen. Glycine and hydroxylysine amino acids (352 and 3 residues 1000g-1, respectively) had the highest and lowest amounts in collagen. Amino acids profile and collagen production efficiency (10.51-10.59%) did not show significant differences in carp fish species (p>0.05). Based on the results of the present study, production efficiency, safety and quality characteristics of collagen in cultured carp species did not show any significant difference (p>0.05), and no significant difference was observed between these characteristics and the control (p>0.05). Therefore, the skin of these species can be used to produce collagen and introduce it to the industry as a substitute for mammalian collagen.
Research Interests:
Global concern about human health and the increase the prevalence of chronic diseases in recent years lead to growing appeals for nutritious and healthy compounds, such as coenzyme Q10. Susceptibility to heat and lipophilic properties of... more
Global concern about human health and the increase the prevalence of chronic diseases in recent years lead to growing appeals for nutritious and healthy compounds, such as coenzyme Q10. Susceptibility to heat and lipophilic properties of coenzyme Q10 limit its utilization in food. Encapsulation is a technology that protects bioactive ingredients from harsh environmental conditions and extends shelf life. The purpose of this study was to encapsulate coenzyme Q10 using complex coacervation by gelatin–basil seed mucilage and characterize physical, thermal and chemical properties of produced microcapsules. Response surface methodology was applied to determine the optimum level of the four formulation variables for maximum encapsulation efficiency, loading capacity and turbidity and minimum supernatant absorption. The optimum microcapsules had encapsulation efficiency of 83.69%, encapsulation load of 16.32%, turbidity of 0.979 and supernatant absorption of 0.227. The microcapsules were assessed by scanning electron microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The results of FTIR confirmed the formation of coacervates. The thermogram of Q10 loaded microcapsule melting point was not observed at its melting point (50°C) due to its solubility in the oil phase and appropriate entrapment. Release behavior of Q10 was studied by different mathematical models. Microencapsulated Q10 was used to fortify milk and the results showed that the developed protein-carbohydrate microcapsules can be applied for protection of hydrophobic compounds.
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Since persimmon is a pressure-sensitive fruit and it is difficult to store this fruit in warehouses, in this research, an attempt has been made to examine the parameters affecting the reduction of changes in its physical properties. The... more
Since persimmon is a pressure-sensitive fruit and it is difficult to store this fruit in warehouses, in this research, an attempt has been made to examine the parameters affecting the reduction of changes in its physical properties. The samples were loaded at 150 and 250 N, three types of foam container packaging with polyolefin film, polyethylene-terephthalate, and ordinary box, and four types of polyamine putrescine coating with concentrations of 1 and 2 mM, distilled water and uncoated. Properties such as Physiological Weight Loss, volume, and the density of persimmon fruit, as well as the firmness of this fruit in the prepost-storage stage were examined. The results showed, the highest firmness was obtained in the treatment of putrescine at a concentration of 1 mM and a foam container with polyethylene film with a value of 6.5 N, which was almost three times the firmness of uncoated fruits. The lowest Physiological Weight Loss, volume, and density were obtained in the same type of coating and packaging. The values of these parameters were 2.458%, 1.82, and 0.833%, respectively, compared to the first day of storage. Overall, the use of polyamine treatment showed a significant effect on changes in the physical properties of persimmon fruit, and foam containers with polyolefin film emerged as the optimal packaging option, resulting in the least amount of change among the different types of packaging used.
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Introduction Thermal process is the most prominent option for treating foods. During the heat treatment, food nutrients response simultaneously but adversely under pH, temperature, moisture, and other provided conditions. It might result... more
Introduction
Thermal process is the most prominent option for treating foods. During the heat treatment, food nutrients response simultaneously but adversely under pH, temperature, moisture, and other provided conditions. It might result in an irreversible transformation of composition and structure that influences oxidative stability and sensory properties. The use of antioxidants is one of the most common methods to prevent edible oils oxidation. Safety concerns of synthetic antioxidants including tert-butylhydroquinone (TBHQ) as food additives have led to increasing demands for natural ones. Phenolic compounds such as Gallic Acid (GA) and Methyl Gallate (MG) represent to possess markedly high activity to scavenge free radicals which are among the most powerful natural sources of oxidative inhibitors in foods. Apart from their antioxidant activity, GA and MG also exhibit multiple biological characteristics such as anti-atherogenic, anti-spasmodic, and anti-microbial activities. This study aimed to investigate the oxidative stability of the in-use sunflower (S) and palm (P) oils as affected by the GA, MG, (GA+MG), and TBHQ to clarify their antioxidant behavior.
Materials and Methods
Antioxidants Gallic acid, Methyl gallate and TBHQ (Purity>98%) were purchased from Sigma Aldrich, USA. All solvents and chemicals were provided from Merck, Germany and Sigma Aldrich, USA with analytical grade. Antioxidant-free sunflower and palm oil were prepared from Three Goals factory, Neyshabur, and potatoes (Agria variety) from Fariman region, Khorasan Razavi.
Results and Discussion
Chemical changes, oxidative stability and quality indices of the in-use sunflower oil (S) and palm (P) (65:35 w.t. %) were evaluated during 8-hour heat treatment at 180 °C through GA, MG, GA/MG (25:75, 50:50 and 25:75) and TBHQ. All experiments were carried out in quadruplicate, and data were subjected to analysis of variance (One-way-ANOVA). Mean data were compared based on Duncan's multiple range test at 5% level (p<0.05). Observations of the chemical properties showed that sample S mainly contained Linoleic fatty acid (61.53%) and Oleic acid (25.50%) and for sample P, Oleic acid (41.90%) and the saturated long-chain fatty acid of Palmitic acid (38.9%). Also, the total phenolic content (TPC) and tocopherol (TTC) of sample P were 53.12 and 185)µg.g-1(, respectively, and sample S were 36.01 and 490 )µg.g-1(. The results of oxidation stability test were analyzed based on Carbonyl value (CV), Conjugated diene value (CDV) and acidity (FFA) parameters. According to our findings, all parameters increased significantly at different speeds during the heat treatment (p<0.05). Moreover, the oxidative stability of the in-use oil was significantly promoted by the antioxidants added, meaning that the control treatment and the treatment containing synthetic antioxidant TBHQ had the highest and lowest FFA%, respectively. The CDV of the antioxidant-free treatment was reduced by 68.6% in the presence of GA75+MG25.In addition, the CV change rate of the antioxidant-free sample in the presence of TBHQ was reduced by 70.2%. It was concluded that the natural antioxidants were capable of being competed with TBHQ antioxidants.
Conclusion
The results of this study showed that the heat treatment affected the nutritional value, quality indexes and chemical structure of the treatments, decreasing the quality and stability of the oil. As observed, all FFA, CDV and CV parameters increased significantly at different speeds during 8-hour frying process. The analysis also indicated that the oxidative stability of the treatments increased at the presence of antioxidants during the heat treatment at 180 °C. Thus, the control treatment and the treatment containing synthetic antioxidant TBHQ had the highest and lowest acidity, respectively. Also, the CDV of the antioxidant-free treatment decreased by 68.6% in the presence of GA75+ MG25. In addition, the rate of CV changes was declined by 70.2% through the TBHQ. The results indicated the key role of this synthetic antioxidant in preventing the formation of secondary compounds in the advanced stages of oxidation.
It is evident that most synthetic antioxidants are volatile and heat sensitive. Furthermore, there are some limitations in applying TBHQ to promote oxidative stability of food products due to its toxic potential. Evidences have also been reported on the mutation caused by the synthetic antioxidant TBHQ in the living organism's body. Compared to synthetic antioxidants, natural polyphenolic antioxidants such as MG and GA which widely distribute in plants mainly have antioxidative properties. Compared to GA and MG, GA+MG antioxidants have a longer induction period and higher oxidative stability. Promoting oxidative stability with such an arrangement of antioxidants is a good option in taking advantage of this class of natural antioxidants. According to the results of this study, it can be inferred that with a slight increase in natural antioxidants levels, we might be able to obtain the oxidative stability level comparable to the behavior of synthetic antioxidant TBHQ. Of course, it is worth noting that the addition of natural antioxidants to food such as edible oils should also be done according to national and international standards.
Thermal process is the most prominent option for treating foods. During the heat treatment, food nutrients response simultaneously but adversely under pH, temperature, moisture, and other provided conditions. It might result in an irreversible transformation of composition and structure that influences oxidative stability and sensory properties. The use of antioxidants is one of the most common methods to prevent edible oils oxidation. Safety concerns of synthetic antioxidants including tert-butylhydroquinone (TBHQ) as food additives have led to increasing demands for natural ones. Phenolic compounds such as Gallic Acid (GA) and Methyl Gallate (MG) represent to possess markedly high activity to scavenge free radicals which are among the most powerful natural sources of oxidative inhibitors in foods. Apart from their antioxidant activity, GA and MG also exhibit multiple biological characteristics such as anti-atherogenic, anti-spasmodic, and anti-microbial activities. This study aimed to investigate the oxidative stability of the in-use sunflower (S) and palm (P) oils as affected by the GA, MG, (GA+MG), and TBHQ to clarify their antioxidant behavior.
Materials and Methods
Antioxidants Gallic acid, Methyl gallate and TBHQ (Purity>98%) were purchased from Sigma Aldrich, USA. All solvents and chemicals were provided from Merck, Germany and Sigma Aldrich, USA with analytical grade. Antioxidant-free sunflower and palm oil were prepared from Three Goals factory, Neyshabur, and potatoes (Agria variety) from Fariman region, Khorasan Razavi.
Results and Discussion
Chemical changes, oxidative stability and quality indices of the in-use sunflower oil (S) and palm (P) (65:35 w.t. %) were evaluated during 8-hour heat treatment at 180 °C through GA, MG, GA/MG (25:75, 50:50 and 25:75) and TBHQ. All experiments were carried out in quadruplicate, and data were subjected to analysis of variance (One-way-ANOVA). Mean data were compared based on Duncan's multiple range test at 5% level (p<0.05). Observations of the chemical properties showed that sample S mainly contained Linoleic fatty acid (61.53%) and Oleic acid (25.50%) and for sample P, Oleic acid (41.90%) and the saturated long-chain fatty acid of Palmitic acid (38.9%). Also, the total phenolic content (TPC) and tocopherol (TTC) of sample P were 53.12 and 185)µg.g-1(, respectively, and sample S were 36.01 and 490 )µg.g-1(. The results of oxidation stability test were analyzed based on Carbonyl value (CV), Conjugated diene value (CDV) and acidity (FFA) parameters. According to our findings, all parameters increased significantly at different speeds during the heat treatment (p<0.05). Moreover, the oxidative stability of the in-use oil was significantly promoted by the antioxidants added, meaning that the control treatment and the treatment containing synthetic antioxidant TBHQ had the highest and lowest FFA%, respectively. The CDV of the antioxidant-free treatment was reduced by 68.6% in the presence of GA75+MG25.In addition, the CV change rate of the antioxidant-free sample in the presence of TBHQ was reduced by 70.2%. It was concluded that the natural antioxidants were capable of being competed with TBHQ antioxidants.
Conclusion
The results of this study showed that the heat treatment affected the nutritional value, quality indexes and chemical structure of the treatments, decreasing the quality and stability of the oil. As observed, all FFA, CDV and CV parameters increased significantly at different speeds during 8-hour frying process. The analysis also indicated that the oxidative stability of the treatments increased at the presence of antioxidants during the heat treatment at 180 °C. Thus, the control treatment and the treatment containing synthetic antioxidant TBHQ had the highest and lowest acidity, respectively. Also, the CDV of the antioxidant-free treatment decreased by 68.6% in the presence of GA75+ MG25. In addition, the rate of CV changes was declined by 70.2% through the TBHQ. The results indicated the key role of this synthetic antioxidant in preventing the formation of secondary compounds in the advanced stages of oxidation.
It is evident that most synthetic antioxidants are volatile and heat sensitive. Furthermore, there are some limitations in applying TBHQ to promote oxidative stability of food products due to its toxic potential. Evidences have also been reported on the mutation caused by the synthetic antioxidant TBHQ in the living organism's body. Compared to synthetic antioxidants, natural polyphenolic antioxidants such as MG and GA which widely distribute in plants mainly have antioxidative properties. Compared to GA and MG, GA+MG antioxidants have a longer induction period and higher oxidative stability. Promoting oxidative stability with such an arrangement of antioxidants is a good option in taking advantage of this class of natural antioxidants. According to the results of this study, it can be inferred that with a slight increase in natural antioxidants levels, we might be able to obtain the oxidative stability level comparable to the behavior of synthetic antioxidant TBHQ. Of course, it is worth noting that the addition of natural antioxidants to food such as edible oils should also be done according to national and international standards.
Research Interests:
Introduction Hydrocolloid is a term refers to all polysaccharides extracted from plants, seeds, and microbial sources that regardless of their biological and nutritional role has various functional properties in food products such as... more
Introduction
Hydrocolloid is a term refers to all polysaccharides extracted from plants, seeds, and microbial sources that regardless of their biological and nutritional role has various functional properties in food products such as concentration and gel production of aqueous solutions, stabilization of foam, emulsions and dispersed systems, prevention of ice and sugar crystals, control of the release of flavor compounds and consequently control and improve food quality. Ultrasound has been widely used in the food industry due to its numerous physical and chemical effects. The effect of ultrasound is due to cavitation, heating, dynamic mobility and shear stresses to the sample. Today, ultrasound is used as a green new technology with unique effects on food storage and processing. One of the newest applications of ultrasound is altering the structure of polymers such as polysaccharides. Changes in the structure of hydrocolloids lead to modification in their functional properties.
Materials and Methods
In this study, effect of ultrasonic waves, time (0-90 min) and processing temperature (25-75 °C) on physicochemical, rheological and functional properties of locust bean gum was investigated. In this regards, different parameters including changes in pH, solubility, minimum gelatinization concentration, viscosity and emulsifying properties (Emulsifying capacity, emulsion stability and particle dimensions) of treated locust bean gum were determined. Response surface methodology in central composite design was used to evaluate the effect of independent variables on qualitative properties of locust bean gum and model their changes. The best treatment condition was determined and the optimum treated samples were evaluated and compared in microstructure using scanning electron microscopy, rheological properties (rotational and oscillatory test) and Fourier transform infra-red.
Results and Discussion
The results showed that with increasing the time of ultrasound treatment, pH, and viscosity of the hydrocolloid decreased and its solubility and minimum gel concentration increased. However, with increasing temperature, pH, minimum gelatinization concentration and hydrocolloid viscosity increased and its solubility decreased. Optimization of treatment conditions was performed by considering the achievement of the best hydrocolloid performance characteristics. Two different temperature and time conditions were proposed for the desirable treatment of the hydrocolloid using ultrasound. In the first case, the selection criteria were to achieve the best solubility and emulsifying properties of the hydrocolloid, and in the second case, the selection criteria were solubility and emulsifying properties improvement while maintaining the gelatinization properties of the hydrocolloid. Based on the desired quality factors, optimization was performed and the results showed that in the first optimal sample (treated at 40 ° C and 48.9 minutes), solubility and emulsifying properties and in the second optimal sample (treated at 66.67 ° C and 15 Min) by maintaining the gelation properties of hydrocolloid, the solubility of the hydrocolloid increased significantly. The performance of treated samples validated developed models. SEM results showed that the ultrasound increased three-dimensional structure of gum. The smaller microscopic structure was observed in untreated sample and the larger one was in treated with ultrasonic waves for 40.9 minutes at 40 ° C. Therefore, ultrasound caused agglomeration of treated freeze dried gum. It is noteworthy that several holes observed in the structure of treated gum with ultrasonic, which can increase solubility of the gum. The flow behavior of the sonicated and control samples showed that the viscosity of all samples decreased with increasing shear rate, which indicates their pseudoplastic behavior. At low shear rates (about 0.01 per second), the viscosity of the control sample was higher than that of the sonicated samples. However, at high shear rates (about 40 per second), viscosity of the three samples were almost the same. Therefore, the control sample was more affective to shear rate compared to the treated samples. The modulus of elasticity (G ') and viscosity (G' ') of the treated specimens were lower compared to the control. Also, the frequency sweep of samples shown that in the frequency range under study, G 'and G'' were frequency dependent and with increasing frequency, the amount of these two parameters increased. This observation indicates the influence of rheological properties of the samples on the frequency changes that are commonly observed in suspensions. At low frequencies, the predominance of viscous behavior over elastic was observed in all three control and ultrasonic samples (G ''> G ') and this feature was higher in the treated samples than the control. The modulus of elasticity and viscosity of the treated sample for 49 minutes was lower than other treated samples for 15 minutes, which shows the effect of ultrasound on the rheological properties of the hydrocolloid.
Conclusion
The results of this study showed that ultrasonic waves provide a good opportunity to change the physical and functional properties of carob seed gum. It is possible to significantly improve the solubility and emulsifying activity of this hydrocolloid using ultrasound. It is necessary to determine the treatment conditions of the sample according to the intended application.
Hydrocolloid is a term refers to all polysaccharides extracted from plants, seeds, and microbial sources that regardless of their biological and nutritional role has various functional properties in food products such as concentration and gel production of aqueous solutions, stabilization of foam, emulsions and dispersed systems, prevention of ice and sugar crystals, control of the release of flavor compounds and consequently control and improve food quality. Ultrasound has been widely used in the food industry due to its numerous physical and chemical effects. The effect of ultrasound is due to cavitation, heating, dynamic mobility and shear stresses to the sample. Today, ultrasound is used as a green new technology with unique effects on food storage and processing. One of the newest applications of ultrasound is altering the structure of polymers such as polysaccharides. Changes in the structure of hydrocolloids lead to modification in their functional properties.
Materials and Methods
In this study, effect of ultrasonic waves, time (0-90 min) and processing temperature (25-75 °C) on physicochemical, rheological and functional properties of locust bean gum was investigated. In this regards, different parameters including changes in pH, solubility, minimum gelatinization concentration, viscosity and emulsifying properties (Emulsifying capacity, emulsion stability and particle dimensions) of treated locust bean gum were determined. Response surface methodology in central composite design was used to evaluate the effect of independent variables on qualitative properties of locust bean gum and model their changes. The best treatment condition was determined and the optimum treated samples were evaluated and compared in microstructure using scanning electron microscopy, rheological properties (rotational and oscillatory test) and Fourier transform infra-red.
Results and Discussion
The results showed that with increasing the time of ultrasound treatment, pH, and viscosity of the hydrocolloid decreased and its solubility and minimum gel concentration increased. However, with increasing temperature, pH, minimum gelatinization concentration and hydrocolloid viscosity increased and its solubility decreased. Optimization of treatment conditions was performed by considering the achievement of the best hydrocolloid performance characteristics. Two different temperature and time conditions were proposed for the desirable treatment of the hydrocolloid using ultrasound. In the first case, the selection criteria were to achieve the best solubility and emulsifying properties of the hydrocolloid, and in the second case, the selection criteria were solubility and emulsifying properties improvement while maintaining the gelatinization properties of the hydrocolloid. Based on the desired quality factors, optimization was performed and the results showed that in the first optimal sample (treated at 40 ° C and 48.9 minutes), solubility and emulsifying properties and in the second optimal sample (treated at 66.67 ° C and 15 Min) by maintaining the gelation properties of hydrocolloid, the solubility of the hydrocolloid increased significantly. The performance of treated samples validated developed models. SEM results showed that the ultrasound increased three-dimensional structure of gum. The smaller microscopic structure was observed in untreated sample and the larger one was in treated with ultrasonic waves for 40.9 minutes at 40 ° C. Therefore, ultrasound caused agglomeration of treated freeze dried gum. It is noteworthy that several holes observed in the structure of treated gum with ultrasonic, which can increase solubility of the gum. The flow behavior of the sonicated and control samples showed that the viscosity of all samples decreased with increasing shear rate, which indicates their pseudoplastic behavior. At low shear rates (about 0.01 per second), the viscosity of the control sample was higher than that of the sonicated samples. However, at high shear rates (about 40 per second), viscosity of the three samples were almost the same. Therefore, the control sample was more affective to shear rate compared to the treated samples. The modulus of elasticity (G ') and viscosity (G' ') of the treated specimens were lower compared to the control. Also, the frequency sweep of samples shown that in the frequency range under study, G 'and G'' were frequency dependent and with increasing frequency, the amount of these two parameters increased. This observation indicates the influence of rheological properties of the samples on the frequency changes that are commonly observed in suspensions. At low frequencies, the predominance of viscous behavior over elastic was observed in all three control and ultrasonic samples (G ''> G ') and this feature was higher in the treated samples than the control. The modulus of elasticity and viscosity of the treated sample for 49 minutes was lower than other treated samples for 15 minutes, which shows the effect of ultrasound on the rheological properties of the hydrocolloid.
Conclusion
The results of this study showed that ultrasonic waves provide a good opportunity to change the physical and functional properties of carob seed gum. It is possible to significantly improve the solubility and emulsifying activity of this hydrocolloid using ultrasound. It is necessary to determine the treatment conditions of the sample according to the intended application.