Full Research Paper
Food Biotechnology
Dina Shahrampour; Morteza Khomeiri; Seyed Mohammad Ali Razavi; Mahboobeh Kashiri
Abstract
Introduction
Increasing public awareness of the impact of diet on health has increased the demand for healthy food products, especially probiotics. Probiotics are living and non-pathogenic microorganisms with beneficial effects on the host when consumed on a regular basis and sufficient amounts ...
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Introduction
Increasing public awareness of the impact of diet on health has increased the demand for healthy food products, especially probiotics. Probiotics are living and non-pathogenic microorganisms with beneficial effects on the host when consumed on a regular basis and sufficient amounts (106 cfu/gr or ml). A significant number of probiotics become inactive during various food processes (thermal, mechanical and osmotic stress), storage condition (exposure to oxygen, UV light and low or high temperature) or during interaction with food ingredients. In addition, the breakdown and passage of food through the digestive system can also affect the survival and ability of probiotics to form colony in the intestine. Therefore, it is a challenge for food manufacturers to maintain and deliver live probiotic cells in sufficient quantities via food product. On the other hand, the variety of probiotic food products in the market, especially in Iran, is low and is mainly limited to dairy products, fermented drinks and pickles. Bioactive edible films and coatings are defined as biopolymer-based structures that carry bioactive components such as vitamins, enzymes, peptides, etc, and slowly release them on the food surface during storage. Biopolymers such as polysaccharides, proteins, and lipids are used in the preparation of edible films and coatings. Trapping probiotic bacteria in the structure of edible films and coatings is a new approach that has been proposed to increase the survival of these microorganisms and to develop new probiotic products in the food industry.
Materials and Methods
In this study, an alginate-based probiotic bioactive film containing L. plantarum was fabricated after centrifuging of overnight culture of probiotic bacterium from MRS medium and adding the bacterial cells into film forming solution. The effect of bacterial addition on physical, mechanical and prevention properties of alginate film was evaluated. In addition, the effect of two temperatures 4 °C and 25 °C on the survival of embedded probiotic bacterium in the film structure during one month of storage was also investigated by microbial count assay on MRS agar medium. Then, the model food was covered with probiotic film and the survival of probiotic bacterium during storage at 4 °C was determined.
Results and Discussion
The results showed that the population of probiotic bacterium declined about 4.61% after drying of alginate film solution. Addition of probiotic bacterium to the alginate film increased the thickness, turbidity, and tensile strength of the film, while had no significant effect on solubility, water activity, Elongation (%) and microstructure of alginate film. In addition, the probiotic film containing bacteria had less Lightness (L*), and moisture content than the control film. Also, the incorporation of L. plantarum in alginate film could decrease the water vapor permeability (WVP) from 0.755 to 4.51 (×10-10 g m-1s-1pa-1). The total color difference (ΔE) of alginate film containing probiotic bacteria compared to control film without probiotic bacteria was 1.1. The SEM images were confirmed the proper and uniform distribution of probiotic L. plantarum cells on the surface of alginate film. The survival percentage of L. plantarum in alginate film after one month of storage at 4 °C and 25 °C was 96.84 and 47.29%, respectively. Also, the population of embedded bacteria in the film structure on the food model (sausage) surface after three weeks storage in refrigerator was in desired level of probiotic products (> 106 cfu / gr).
Conclusion
The viability of probiotic bacteria after the application of alginate film containing L. plantarum on the surface of food model (sausage) during cold storage remained at the optimal recommended level for three weeks. Therefore, alginate film is recommended as a suitable carrier for probiotic microorganisms to produce new functional products.
Full Research Paper
Food Engineering
Mohaddese Ahmadi; Hadi Samimi Akhijahani; Payman Salami
Abstract
IntroductionSolar energy is one of the sources of renewable energy that can be used in both buildings, industry and agriculture in the form of heat or electrical energy. According to previous researches, energy consumption in the world is doubling every 20 years. However, the use of renewable energy ...
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IntroductionSolar energy is one of the sources of renewable energy that can be used in both buildings, industry and agriculture in the form of heat or electrical energy. According to previous researches, energy consumption in the world is doubling every 20 years. However, the use of renewable energy is still less than fossil fuels, which has caused environmental problems in the world. In recent decades, the tendency to use renewable energy, especially solar energy, has increased. A significant portion of the world's energy (about 30%) is spent on agriculture, and about 3.62% is used to dry agricultural products (Iranmanesh et al., 2020). However, thermal and drying efficiency of the solar collectors are not in acceptable range. Applying different ways to improve the performance of solar dryers such as using thermal energy storage system, air recirculation mechanism and using desiccant system. In this paper, phase change materials were placed vertically in consecutive rows at different distances inside the collector and the thermal performance of the collector was investigated. Also, the drying process of Oleaster were evaluated using PCM and air recirculation system. Materials and MethodsThe indirect solar dryer used in this study includes the chassis, flat plate collector, electric fan, drying cabinet, pipes containing PCM and sensors. 25 copper tubes containing PCM are placed on the absorber plate with fixed intervals. The insulated cabinet of the dryer has three trays. A 220 volt 60 W electric fan is placed in the inlet of the collector and causes to flow air inside the system. The process of drying Oleaster in a solar dryer was carried out for 9 consecutive days in August 1401. The drying process was performed at three positions of PCM pipes at 5, 10 and 15 cm intervals with air flow rate of 0.5, 1 and 2 m/s. The drying kinetics of Oleaster was investigated using five mathematical models considering drying time and related constants. The selected model is selected based on the degree of fit (the highest R2 and the lowest RMSE) on the experimental data. Thermal efficiency was calculated according to ASHRAE standard 2003 (Eltawil et al., 2018). Moreover, to determine the drying efficiency the amount of energy required to heat the dryer and the product and extract water from the Oleaster and the total energy (electrical and thermal) input to the dryer was considered. SCE is defined as the energy required to dry one kilogram of the product. Results and DiscussionThe drying time of the product by the dryer is reduced from 2.09 to 4.16% on average by changing the position of PCM from 5 cm to 15 cm. On the other hand, with the increase of air velocity from 0.5 to 2 m/s, the drying time decreased from 8.32% to 16.64%. Henderson and Pabis model was the best model to describe and define the drying process of Oleaster with solar dryer. The curves of the drying rate against the time in different conditions illustrated that in the initial stage of drying of samples. The amount of moisture evaporation is high due to the high water content in Oleaster, and a major part of the drying process took place in this period. The value of SEC for the dryer without PCM was 4.26 MJ/kg, while for the case with PCM, it was 2.04 MJ/kg with a distance of 15 cm. By increasing the distance between the tubes, the drying efficiency increases due to the reduction of drying time and energy consumption. In this case, the consumption of electrical energy by the fan (for fluid flow in the dryer and collector) and the thermal energy input to the dryer are reduced. However, with the increase of air speed from 1 m/s to m/s2, there is a significant reduction in drying efficiency. The highest drying efficiency was 36.72% and the lowest was 25.65% for distance 15 cm, air velocity of 1 m/s and distance 5 cm, air speed 2 m/s, respectively. Drying efficiency was improved by at least 12% using PCM. ConclusionIn this research, the analysis of the thermal process in the solar dryer system in three positions of the tubes containing PCM inside the flat plate collector for the distances of 5, 10 and 15 cm between the tubes at three air velocities of 0.5, 1 and 2 m/s was investigated. Using the return flow system and the phase changing material at the same time improved the thermal efficiency of the flat plate collector by 19.12%.
Full Research Paper
Food Chemistry
Mozhgan Akbari; Reza Farhoosh; M. Moeenfard
Abstract
IntroductionToday, many edible oils such as palms, corn, soybeans and sunflowers are used in food preparation. Essential oleic, linoleic and linolenic fatty acids, found abundantly in olive, sunflower and soybean oils, respectively, play an important role in maintaining health. Antioxidant compounds ...
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IntroductionToday, many edible oils such as palms, corn, soybeans and sunflowers are used in food preparation. Essential oleic, linoleic and linolenic fatty acids, found abundantly in olive, sunflower and soybean oils, respectively, play an important role in maintaining health. Antioxidant compounds are used to increase the shelf life of oils, which are classified into two groups of natural and synthetic antioxidants based on the source of production. Phenolic acids are a subset of a large group of phenolic compounds that are used as natural antioxidants in industry. Gallic acid is much stronger than protocatchuic acid due to its three hydroxyl groups. However, the presence of more than three hydroxyl groups does not seem to increase the antioxidant effect in oily systems. The position of the hydroxyl group on the aromatic ring also affects the antioxidant activity, so that the replacement of the hydroxyl group in the ortho and para position increases the antioxidant activity of phenolic acids. Methyl gallate, which is widely found in plants and polyphenolic secondary metabolites, is a natural antioxidant. Despite efforts to date, no suitable natural antioxidant has been proposed to control the thermal oxidation of oils at high temperatures. Therefore, due to the widespread use of oils in food, the thermal stability of natural antioxidants gallic acid and methyl-gallate compared to the powerful but synthetic antioxidant TBHQ, depending on the degree of satiety of the lipid system (sunflower oil and olive oil) and 80 degrees Celsius will be evaluated in this study. Material and MethodsSamples of sunflower and olive oil were purchased from local stores. All chemicals and solvents were provided by Merck and Charlot. Sunflower and olive oil were purified by column chromatography to remove natural antioxidants. Oxidation of purified sunflower oil (1 g per oil) in the presence of a concentration level of gallic acid, methyl gallate and TBHQ (1.2 μmol/g) in glass bottles. The rate of progression of oxidative reactions and the evaluation of oil quality during temperature application is possible by measuring the peroxide number. The carbonyl number is determined using 2-propanol as solvent and 2,4 decodenal as standard and absorbance at 420 nm. The effect of antioxidants (InH) on the oxidation of the test samples can be measured based on the kinetic parameters. These parameters are stability factor F, ORR oxidation rate ratio, activity A and average consumption of WInH antioxidants. Results and DiscussionThe minimum and maximum induction times are related to the control sample and the sample containing the synthetic antioxidant TBHQ, respectively, which, considering the position of the two hydroxyl groups in the para position relative to each other in the TBHQ molecule, make this antioxidant stronger. Justifies. At 80 °C and in sunflower oil, the antioxidant methyl gallate shows a more effective stability factor (F) and antioxidant activity (A), indicating greater antioxidant power than gallic acid. Similarly, F-ORR-A values in methylgalate treatment have a significant effectiveness compared to other treatments. The higher oxidative stability of olive oil against sunflower oils can be attributed to the small amounts of oleic acid and especially the small amounts of linolenic acid in olives. Stability factor (F), is significantly higher for the TBHQ antioxidant than the values obtained for the other two. This factor is affected by the induction period of antioxidants and can be expected due to the effectiveness of antioxidants in increasing the duration of the induction period. The highest value obtained for the ORR oxidation rate parameter, is related to the antioxidant gallic acid. The parameter of antioxidant activity A, in TBHQ is higher than the other two antioxidants. Measurement of carbonyl compounds resulting from the decomposition of hydroperoxides is a good measure of the rate of development of oxidative reactions. In the treatment of gallic acid and TBHQ, the changes in the carbonyl number decrease at the end of the annealing, which is probably due to the decomposition of carbonyl compounds and the production of polymer compounds. Which cannot be measured by carbonyl number test. ConclusionBetter efficacy of gallic acid compared to methyl gallate in olive oil and better efficacy of methyl gallate compared to gallic acid in sunflower oil at 80 °C show the composition of fatty acids, the nature of lipid systems and the position of antioxidants in the reaction medium. Have a great effect on improving the performance of antioxidants. Determination of oxidative stability based on carbonyl number shows similar results to peroxide number .
Short Article
Food Technology
Rahman Yousefi; Mohammadreza Pourghayoumi; Seyyed Samih Marashi; Ali Ghasemi
Abstract
IntroductionDate palm (Phoenix dactylifera) is one of the most important horticultural products in arid and semi-arid regions of Iran. One of the factors affecting the quality and nutritional elements of date fruit- as an important and strategic fruit in the country, with high nutritional and health ...
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IntroductionDate palm (Phoenix dactylifera) is one of the most important horticultural products in arid and semi-arid regions of Iran. One of the factors affecting the quality and nutritional elements of date fruit- as an important and strategic fruit in the country, with high nutritional and health value- is the proper use of different nutritional elements during its growth and fruiting period. There are many reports of the negative effects of salinity on dates, both in the vegetative and reproductive growth stages. The osmotic effects limiting the absorption of water and nutrients, the specific effect of chlorine and sodium ions, nutritional imbalance and preventing the physiological processes and metabolism of nutrients and the use of high energy in osmotic regulation are some of the negative effects of salinity stress. Salinity stress negatively affected date fruit quality. Silicon is one of the essential nutrients that plays an important role in the growth and development of plants. Silicon reduces the adverse effects of abiotic stresses such as drought and salinity by affecting on the leaf and stem growth, and other plant mechanisms. Therefore, the aim of this study was to investigate the effect of foliar application of silicon on some qualitative characteristics and nutrient elements content of date fruit grown under high salinity soil. Materials and Methods This research was conducted in a randomized complete block design with 7 treatments and 3 replicates in two consecutive years. Silicon foliar spray treatments consisted of: control or no application of foliar spraying (T1), foliar spraying with a concentration of 0.1% in two stages (T2), foliar spraying with a concentration of 0.1% in three stages (T3), foliar spraying with a concentration of 0.2% in two stages (T4), foliar spraying with a concentration of 0.2% in three stages (T5), foliar spraying with a concentration of 0.3% in two stages (T6) and foliar spraying with a concentration of 0.3% in three stages (T7). The treatments were repeated in two consecutive years, and in each fruiting season, fruit quality characteristics including total soluble solids (TSS), acidity (TA), pH and total sugar content were measured. Total sugar was measured according to Iran's national standard method No. 2685 (ISIRI, 2007). The concentrations of potassium, calcium, iron and zinc were also measured at the end of the second year of the experiment. Fruit quality characteristics and concentration of fruit nutrients were measured and statistically analyzed. Results and DiscussionFoliar application of silicon fertilizer significantly increased the TSS of ‘Barhee’ date fruits while it decreased the pH of fruit juice. The lowest amount of total soluble solids was observed in T1 treatment at the rate of 63.69% and the highest amounts of fruit soluble solids were recorded in T5 and T6 treatments with values of 70.07% and 68.59% respectively. Fruit acidity and total sugar were not affected significantly by foliar application of silicon. The application of silicon significantly increased the contents of potassium, calcium, iron and zinc in date fruit, but it had no significant effect on the concentration of phosphorus in the fruit. The highest concentration of fruit potassium was observed in the T6 treatment (spraying with 0.3% silicon solution in two stages) at the amount of 1.54%. The lowest values of potassium concentration were observed in T3, T2 and T1 treatments with values of 0.89%, 1.01% and 1.06% respectively. Overall, Foliar application of silicon fertilizer can improve the quality characteristics and nutrient concentration of date fruit under salinity stress conditions. Among all the treatments, foliar application of silicon fertilizer with a concentration of 0.3% in two stages (three weeks before pollination and at the end of the Hababook stage) improved quality characteristics and the nutrient elements of ‘Barhee’ date fruit under high salinity soil.
Full Research Paper
Food Technology
Ali Akbar Shokouhian; Shahriyar Einizadeh; Mehrdad Dashti
Abstract
IntroductionCherry, with the scientific name Prunus avium L., is one of the most important stone fruit trees in temperate regions, belonging to the Rosaceae family and the Prunoideae subfamily. Edible coatings are thin layers of materials that are used on the surface of the product and are an alternative ...
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IntroductionCherry, with the scientific name Prunus avium L., is one of the most important stone fruit trees in temperate regions, belonging to the Rosaceae family and the Prunoideae subfamily. Edible coatings are thin layers of materials that are used on the surface of the product and are an alternative to protective wax coatings. Chitosan is a coating that has a polysaccharide structure and is composed of glucosamine and N-acetylglucosamine units and is obtained from the shell of crustaceans such as crabs and shrimps. Clear, odorless, non-sticky gel with high and firm absorption power is extracted from the inner parts of aloe vera plant leaves. Between this gel and the outer skin of the leaf, there are special cells that contain a yellow liquid and when this liquid dries, aloe vera juice is produced. This gel is completely healthy and compatible with the environment, and its pH is about 4.5, which can replace various fruit coatings in the post-harvest stage. The purpose of this research was to investigate the combined effect of aloe vera gel and chitosan in maintaining the quality characteristics post harvesting and increasing the shelf life of Lombard cherry fruit. Materials and MethodsLambert black cherry fruit was obtained from the garden complex of Moghan Agriculture and Animal Husbandry Company located in Pars Abad city of Ardabil province. they were immediately transferred to the Postharvest Physiology Laboratory, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, Mohaghegh Ardabili University, for the desired treatments.This study aimed to extend the shelf life of cherry fruit with two edible chitosan coatings (0, 0.5, 1, 1.5% w/w) and aloe vera gel (0, 15%, 30%, 45% w/w) was performed as factorial in a completely randomized design in three replications. The measured parameters were soluble solids, vitamin C, total acidity, anthocyanin, starch, weight loss and firmness of fruit tissue that were evaluated at harvest time and 45 days after harvest. Results and DiscussionThe results of analysis variance showed that the effect of time had significant on cherry fruit flavor (P<0.01). The use of Aloe vera gel had a significant effect (P<0.01) on soluble solids, starch, firmness, fruit flavor and also weight loss (P<0.05). The effect of chitosan treatment also were significant on total soluble solids, starch, firmness, and fruit flavor (P<0.01). Moreover, Interaction effect of aloe vera gel and chitosan treatments on total soluble solids, starch, firmness, and fruit flavor were significant (P<0.01) during at storage time. The compare means showed that the ratio of soluble sugars to total acid was increased. The highest soluble solids and their ratio to total acid were obtained as a result of the using of 45% aloe vera gel with 0.5% chitosan coating. Combining of aloe vera gel with 30% and 45% concentrations with chitosan at 1% and 1.5% were able to maintain better firmness of fruit tissue compared to other treatments during storage time.The highest residual starch in the fruit was obtained in using aloe vera gel treatments at concentrations of 15%, 40% and 45% with 1% chitosan during storage. Also, the use of aloe vera gel (all three levels) was exceled compared to control on fruit weight loss. By reducing the activity of ethylene, chitosan causes a delay in ripening and aging and as a result reduces the firmness of the fruit. Aloe vera gel reduces the activity of pectin methylesterase, poly-galactronase and beta-galactosidase. These enzymes destroy the cell wall and soften the fruit. ConclusionThe interest in using edible coatings to maintain the optimum quality of fruits during the marketing and storage process has increased. Edible coatings can act as a barrier, thereby reducing quality loss, inhibiting gas exchange, controlling respiration rates, and preventing the growth of microorganisms that cause fruit decay. The results clearly indicated the preservation of the quality of cherry fruit with the use of edible coatings compared to the control. The use of the treatment combination of chitosan at a concentration of 1.5% with aloe vera at a concentration of 45% has had a positive and significant effect to maintain the quality of cherry fruit after harvesting. Therefore, the use of this treatment combination is recommended to increase the storage life and maintain the quality of Lambert cherry fruit during the storage period.
Full Research Paper
Food Technology
Aliakbar Gholamhosseinpour; Ali Karimi Davijani; Mostafa Karami
Abstract
Introduction
Cheese is the general name of a group of fermented dairy products that are produced all over the world in a variety of flavors, textures, and shapes. This product considered a source of protein, minerals, and vitamins, all of which add to its high nutritional value. White-brined cheeses ...
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Introduction
Cheese is the general name of a group of fermented dairy products that are produced all over the world in a variety of flavors, textures, and shapes. This product considered a source of protein, minerals, and vitamins, all of which add to its high nutritional value. White-brined cheeses are soft cheeses that ripen in brine. Brined ultrafiltered cheese, as a popular product, has attracted a broad consumer market in our country. The use of thermal processes to prolong the shelf life of foods has long been considered, but these methods lead to a decrease in nutritional value and product quality. Emerging non-thermal technologies, including ultrasound, pulsed electric field, high hydrostatic pressure, cold plasma and ozone have revolutionized the food processing sector. These processes can improve the safety and quality of food products and increase their shelf life by reducing food spoilage. In addition to expanding food shelf life, these technologies are experiencing more orogress in the industry due to reduced energy consumption. Ozone is one of the most effective disinfectants known that does not leave any dangerous residue on food or other surfaces in contact. Ozone treatment does not require heat and therefore saves energy. Ozonation, as a novel technology, is widely used in preserving meat, processing oysters, inhibiting microbial growth, and oxidizing phenolic compounds. Ozone has been mainly used in the dairy industry to reduce or inhibit the growth of pathogenic or spoilage microorganisms. However, its effect on the non-microbial properties of dairy products has not been studied much.
Materials and Methods
Cheese production was carried out by ultrafiltration technology in the Hamedan Pegah dairy complex (Hamedan, Iran). The starter culture used in cheese production was R708 (containing Lactococcus lactis subsp. cremoris and Lactococcus lactis subsp. lactis), which was obtained from Christian Hansen, Denmark. Microbial renin enzyme (Proteria, Handry Company, Belgium) was also used for coagulation. Analytical grade chemicals were also purchased from Merck, Darmstadt, Germany. Ozone gas at concentrations of 2 and 5 ppm was used in different stages of brined ultrafiltered cheese production and then the samples were subjected to physicochemical (total solids (TS), ash, pH, salt, protein, fat, acid degree value (ADV)), microbiological and organoleptic (based on the 5-point hedonic scale) analyses at 35-day intervals during a ripening period of 105 days. The studied treatments were: Ozonization of retentate simultaneously with starter inoculation (OA), Ozonization of retentate before starter inoculation (OB), Ozonization of retentate (before starter inoculation) and brine (OC), Ozonization of brine (OD) and control (C). Statistical analysis (One-way ANOVA and Duncan) was performed at a significance level of 95% by the SPSS package program (v. 20.0, Chicago, IL, USA).
Results and Discussion
Based on the results, the amounts of total solids, ash, salt, ADV and syneresis of cheeses increased significantly (p ≤ 0.05), while the protein and fat contents of the samples decreased significantly (p ≤ 0.05) during the ripening period. The pH of the samples decreased from day 0 to 35 and then increased in most samples until the end of the ripening period. The total counts in the samples increased initially until day 70 but then decreased until the end of the ripening period. In general, during the ripening, cheeses treated with 5 ppm ozone had lower microbial load and higher lipolysis compared to samples treated with 2 ppm ozone. In addition, in most treatments, the sensory scores of cheese samples at the end of the ripening period were significantly (p ≤ 0.05) higher than those at the beginning of the ripening period. The application of ozone treatment was able to improve some of the sensory properties of the cheeses. In general, this improvement was not statistically significant compared to the control, especially at the end of the ripening period.
The positive microbial and physicochemical effects of ozone treatment on cheese samples leading to increase the shelf life of brine cheese up to 105 days (30 days more than usual) without having a negative effect on its sensory properties. Therefore, ozone can be used as a non-thermal treatment to extend shelf life and improve some physicochemical characteristics of cheese.
Full Research Paper
Food Biotechnology
Asma Entezari; Nasser Sedaghat; Golshan Shakeri
Abstract
Introduction The main sources of Salmonella for humans are pork, beef, chicken, eggs, fruits, vegetables, and their derivatives such as mayonnaise, and peanut butter. Different species of Salmonella can adapt, grow or survive at different environmental conditions. Salmonella enterica is a majorcause ...
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Introduction The main sources of Salmonella for humans are pork, beef, chicken, eggs, fruits, vegetables, and their derivatives such as mayonnaise, and peanut butter. Different species of Salmonella can adapt, grow or survive at different environmental conditions. Salmonella enterica is a majorcause of food borne illness in humans, and Salmonella typhimurium and Salmonella enteritidis serovars are the most prevalent. One strategy is to use active packaging to reduce the microbial load or prevent the growth of microorganisms on food. Recently, antimicrobial active packaging has received much attention due to maintaining food quality, safety, and increasing shelf life. Among the antimicrobials used in the food industry, bacteriophages have a very good efficiency to control pathogenic bacteria. Pullulan has a good ability to form a film, its film has good characteristics such as transparency, odorlessness, tastelessness, solubility in water, and low permeability to oxygen and fat, However, the major obstacle is related to its price. The combination of polysaccharides with proteins has been done in order to improve the performance and reduce the costs of films. Gelatin is a suitable option to combine with pullulan in terms of good mechanical properties, reduced permeability, and its good price. Different ratios of gelatin and pullulan were studied and suitable film selected, but it needed to modify, so nanofibers cellulose was added in order to improve the mechanical properties and water resistance. Adding cellulose nano fiber can be a good and appropriate option. The aim of this research was to evaluate theantibacterial effectiveness of gelatin-pullulan- nanofibers cellulose composite film containing bacteriophage against Salmonella typhimurium at two different temperatures. Materials and MethodsGelatin and pullulan powders were weighted separately and mixed together (20gelatin-80pullulan). Nanofiber cellulose was extracted from rice bran and was used at three different levels (1%, 3%, and 5%). Commercial bacteriophage solution was added to each of the films separately and the films were prepared by molding method. Thickness, moisture content, solubility, swelling, tensile strength, and elongation of gelatin-pullulan film containing nanofibers were studied. Zone inhibitory of films containing different percentage of cellulose nanofibers on the agar media against Salmonella typhimurium (104 CFU.ml-1) was evaluated. The, antibacterial effect of selected film on the poultry meat inoculated with S. typhimurium (104 CFU.g-1) and several phages on the surface meat at 4 and 12 was also investigated. Results and Discussion The results indicated that gelatin-pullulan films containing different percentages of cellulose were showed approximately 2 mm of zone inhibitory compare to films free of phages. Also, inhibitory among films at different percentage of nanofiber cellulose did not show significant change. Antibacterial effect on poultry meat was dependent on temperature, films loaded with bacteriophages at higher temperature (12 ) was more effective compare to lower temperature (4 ). The populations of S. typhimurium were decreased 1 log and 0.7 log than control samples at 4 after 7 and 9 days respectively, while at 12 , 1 log and around 2.55 log decrease was found after 1 and 9 days, respectively. In a study, beef inoculated with salmonella was treated by SALMONELEXTM bacteriophage and resulted in 1.29 log reduction of pathogenic bacteria compared to the control sample (Yeh et al., 2017). In another study, the antibacterial effect of double-layer poly lactic acid/xanthan film at 10 °C compared to 4 °C against pathogenic bacteria of Salmonella and Listeria was determined and found that at10 °C, the number of pathogenic bacteria was decreased more than at 4 °C (Radford et al., 2017).. Kamali et al. (2022b) reported that the release of phages from the film of 30 poly lactic acid/70 whey protein to the meat surface after one hour was 63.22 % and 63.18 % at 4 °C and 10 °C, respectively, which means no significant difference, after one day at both temperatures.
Full Research Paper
Food Technology
Ali Hashemi Shaktai; Jafar Mohammadzadeh Milani; Ali Motamedzadegan; Sepide Haghighat-Kharazi
Abstract
Introduction Due to the low amount of prolamin, rice flour is the most suitable raw material for preparing food for patients with celiac disease. Particle size classification and thermal treatments are among the physical methods to improve the functional characteristics of gluten-free flours and ...
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Introduction Due to the low amount of prolamin, rice flour is the most suitable raw material for preparing food for patients with celiac disease. Particle size classification and thermal treatments are among the physical methods to improve the functional characteristics of gluten-free flours and as a result, improve the quality of the products obtained from them. Particle size can increase the quality of gluten-free products by affecting the physicochemical properties of flour during hydration. Dry heat treatment and moist heat treatment are common techniques for physical modification which, depending on the intensity of temperature and storage time, lead to the improvement of gluten-free products by modifying starch grains, aroma, and flavor, and reducing microbial load. Considering that the effect of rice flour particle size on the quality of gluten-free bread has not been studied so far, in the current research, by dividing rice flour into particles with sizes of 180, 150, and 125 microns and using moist and dry heat treatments, The possibility of improving the functional characteristics of rice flour and improving the quality characteristics of gluten-free bread were investigated. Materials and Methods The content of moisture, pH, ash, and protein of rice flour was measured using AACC standard method (2000) and the total amount of starch was measured by the alkaline extraction method and the amount of starch damage was measured by non-enzymatic rapid method. To classify the size of the particles, waxy rice flour was divided by a shaker sieve with different sizes of 180, 150, and 125 microns, then under the influence of dry heat treatment for 2 hours and moist heat treatment with 25% humidity for 5 hours at a 110°C To produce gluten-free bread, the formulation used by Haghighat‐Kharazi (2020) was used with a slight change. Ingredients for gluten-free bread formulation for 100 grams of rice flour included 125 ml of water, 4.5 grams of sugar, 2 grams of salt, 6 grams of vegetable oil, 3 grams of yeast, and 2 grams of xanthan gum. Bread characteristics, which include weight loss, specific volume, oven spring, crumb crust ratio, shape index, porosity, crust and crumb color, and bread texture analysis were studied to evaluate the quality of bread. Finally, the factorial test was used to investigate the effects of particle size and heat treatment of rice flour, and Duncan's multiple range test was used to compare the means at the 5% probability level. Results and Discussions The results showed that the effect of particle size on weight loss, specific volume, oven spring, crumb to crust ratio, crust, and crumb color parameters, and bread texture was not significant (p>0.05). Regarding the sample volume index, C80 and DHT120 significantly had the lowest volume index (p<0.05). The HMT80-treated sample significantly increased the weight loss, and the moist heat-treated samples significantly increased the specific volume and the core to shell crumb (p<0.05). Sample treated with HMT 120 had the highest volume index. moist heat treatment and dry heat led to significantly decrease in brightness and an increase in the yellowness of the crust and crumb of the bread compared to the control sample, but there was no significant change in the amount of redness (p<0.05). Moist heat treatment samples had the lowest hardness and chewiness compared to the control sample and the dry heat treatment sample. In general, the sample obtained from 125-micron flour particle size and moist heat treatment led to the improvement of gluten-free bread quality.
Full Research Paper
Food Chemistry
Zeinab Nooshi Manjili; Alireza Sadeghi Mahoonak; Vahid Erfani Moghadam; Mohammad Ghorbani; Hoda Shahiri Tabarestani
Abstract
Introduction
Seeds and nuts have received increasing attention due to their nutritional value and the high therapeutic properties of their bioactive compounds. Most of the seeds are used as nuts, and some of them are considered agricultural waste. Pumpkin seeds have a high content of protein (30–40% ...
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Introduction
Seeds and nuts have received increasing attention due to their nutritional value and the high therapeutic properties of their bioactive compounds. Most of the seeds are used as nuts, and some of them are considered agricultural waste. Pumpkin seeds have a high content of protein (30–40% in terms of dry matter). Proteins are among the vital health-giving components that provide nitrogen, essential amino acids and energy necessary for normal cells. Pumpkin seeds are a good source of amino acids such as valine, histidine, isoleucine, leucine, threonine and methionine. Protein hydrolysate is a mixture of peptides and amino acids that can show antioxidant, antimicrobial, anticancer, antidiabetic and antihypertensive properties. During hydrolysis, proteins are broken into small peptides and amino acids. Since enzymatic hydrolysis is performed in relatively mild conditions and no amino acid damage occurs, this type of hydrolysis is preferred over acid and alkaline hydrolysis. Hydrolysates obtained from pumpkin seed protein have bioactive properties, especially antioxidant activity. Pretreatment of proteins before enzymatic hydrolysis acts to improve the release of bioactive peptides from different proteins. Pretreatment can facilitate the unfolding the structure of proteins and thus increase the access of enzymes to peptide bonds. The main properties of microwaves usually show three characteristics: penetration, reflection and absorption. Microwave assisted enzymatic hydrolysis can shorten the time and improve the speed of the reaction. The purpose of this research was to investigate the antioxidant activity of pumpkin seed protein hydrolysates (Cucurbita maxima L.) by alcalase enzyme in two conditions: without pretreatment and using microwave pretreatment.
Material and Methods
In this study, Pumpkin (Cucurbita maxima L.) was purchased from the local market of Astane Ashrafieh in Gilan province. The seeds were scooped manuallyand then dried in an oven at 50°C for 72 hours. After the production of protein concentrate from pumpkin seeds, the chemical properties of the concentrate, such as the amount of fat, protein, ash and moisture, were measured. The isolated pumpkin seed solution was exposed to microwave energy with a power of 450-900 watts for 30–90 seconds and was used as a substrate solution in enzymatic hydrolysis experiments. It should be noted that after measuring the total antioxidantactivityr for different powers and times of microwave pretreatment, the power of 600 watts for 60 seconds was selected and applied before enzymatic hydrolysis. Enzymatic hydrolysis was done by alcalase enzyme with a concentration of 0.5 to 2.5% compared to the protein substrate during 20 to 190 minutes, and the optimum temperature and pH of alcalase were determined in order to produce hydrolysates with antioxidant activity. Antioxidant activity was measured by using DPPH free radical inhibition, total antioxidant activity and iron chelation activity methods.
Result and Discussion
Bioactive peptides produced by the enzymatic hydrolysis of proteins have significant antioxidant properties. Pumpkin seeds can be used as a rich source of nutrients and bioactive compounds in various food industries. The results showed that the maximum amount of antioxidant activity without pre-treatment was achieved in 165 minutes with a 2.2% ratio of E/S by using DPPH free radical scavenging activity (40.5%), total antioxidant power (0.79), and iron chelation activity (96.2%) methods. By using microwave pre-treatment, the maximum amount of antioxidant activity was achieved in a shorter time and with less enzyme (105 minutes and E/S ratio 1.5%) using DPPH free radical scavenging (52%), total antioxidant power (0.711), and iron chelation activity (93%). Therefore, it can be concluded that using microwave assisted enzymatic hydrolysis , in addition to achieving hydrolysates with proper antioxidant activity, is a suitable method to save time and reduce enzyme concentrations used in enzymatic hydrolysis.
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Food Technology
Parisa Feizi; Yahya Maghsoudlou; Hoda Shahiri Tabarestani; Seyed Mahdi Jafari; Amir Bahri
Abstract
Introduction Astaxanthin is a widely used carotenoid pigment in the food industry which is extracted from various natural and synthetic sources. Nowadays, due to the adverse effects of organic solvents green solvents which are non-toxic, non-volatile and environmentally friendly have been proposed. ...
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Introduction Astaxanthin is a widely used carotenoid pigment in the food industry which is extracted from various natural and synthetic sources. Nowadays, due to the adverse effects of organic solvents green solvents which are non-toxic, non-volatile and environmentally friendly have been proposed. Therefore, this study focuses on comparison of the extraction of astaxanthin from shrimp (Fenneropenaeus merguiensis) and Gammarus (Pontogammarus maeoticus) under soaking conditions for 24 hours with organic solvent (combination of ethanol with ethyl acetate), green solvent (microemulsion of ionic liquid in water) and vegetable oil (sunflower oil). Ionic liquid microemulsion in water is considered a newnovel solvent for astaxanthin extraction. Determination of density, conductivity and diameter were the characteristics of microemulsion test. In extraction,Solvent to sample ratios of 5x, 12.5x and 20x were used for the extraction and compared with the control sample. Materials and Methods merguiensis and P. maeoticus With species approval were procured from Persian Gulf Ecology Research Institute (Iran). Commercial astaxanthin (>98 % purity), α-diphenyl-β-picrylhydrazyl (DPPH), and butylated hydroxytoluene (BHT) were procured from Sigma-Aldrich (USA). The HPLC grade ethanol, propanol, ethyl acetate,, tributyl octyl phosphonium bromide, Triton X-100, and n-butanol were obtained from Merck Chemicals Co. (Germany). Refined sunflower oil which was antioxidant-free, was also purchased from Hayat Company (Iran). The shell of F. merguiensis and P. maeoticus were carefully washed with distilled water, then freeze-dried (Christ-Alpha 1–4, LD freeze dryer, Germany) for 48 h at -50 °C. After sieving the powders with a laboratory sieve with a mesh smaller than 15 µm. The obtained powders were kept at Refrigerator. All experiments were done in the Food and Drug Administration Department of Hormozgan University of Medical Sciences. Results and Discussion According to the results, the density of the microemulsion was determined in the range of 0.97151 g/cm3, its diameter was 15.8 nanometers and the conductivity was 312 microsiemens at 27.1°C. The results of astaxanthin extraction with different solvents in the comparison with control solvent were statistically significant (p< 0.05). According to the results obtained from the extraction of astaxanthin from two sources of shrimp and gammarus, shrimp was selected as the source with the highest amount of extracted astaxanthin. The use of green solvent (ionic liquid microemulsion in water) in a ratio of 12.5 times solvent to sample was also chosen as the optimal method. The amount of astaxanthin extracted under optimal conditions was 77.44 ± 1.09 mg/ml. The results of DPPH radical inhibition by extracted astaxanthin using ionic, oily and organic solvents compared to synthetic antioxidant BHT showed that the antioxidant activity increased with increasing the concentration of astaxanthin, but this increase was always lower than BHT. ConclusionIn general, the results of this research show that the use of microemulsion based on ionic liquids is a suitable alternative to conventional methods in extracting and recovering astaxanthin from natural biological sources. AcknowledgementWe are grateful to the Honorable Vice-Chancellor of Hormozgan Food and Drug Administration for the help in using the Hormozgan Food and Drug Laboratory to conduct the experiments of this doctoral thesis.
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Food Technology
Bahareh Shabanpour; Parastoo Pourashouri; Aniseh Jamshidi; Kaveh Rahmani farah; Akbar Vejdan Taleshmikaeil
Abstract
Introduction Consumption of ready-to-eat products especially seafood, has become very popular based on the lifestyle during these years. Battered and breaded products are highly acceptable due to their attractive appearance and unique taste. Shrimp and shrimp products are one of the most popular ...
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Introduction Consumption of ready-to-eat products especially seafood, has become very popular based on the lifestyle during these years. Battered and breaded products are highly acceptable due to their attractive appearance and unique taste. Shrimp and shrimp products are one of the most popular seafood products in many countries because of their unique flavor, nutritional value and texture. The interactions of proteins with other ingredients can play a critical role in the structure of processed foods. Protein-polysaccharide interactions provide functional properties in foods especially when proteins are the main ingredients, such as processed shrimp products without affecting the original flavor of the food. The use of gelling properties of carbohydrates in the formulation of food products is increasingly growing. The wide variety of hydrocolloids have been examined to modify the mechanical, textural and functional properties of shrimp products. In this regard, application of carrageenan, xanthan, and alginate have been reported to improve the physicochemical and sensory attributes of shrimp products. In the present study, surimi was produced and used in combination with different percentages of carrageenan, alginate and xanthan gums in order to simulate breaded shrimp and produce shrimp nuggets with a texture similar to battered and breaded shrimp. Materials and Methods In the first step, surimi was prepared from silver carp fillets. In the next step, shrimp nuggets were produced from obtained surimi in combination with additives (including starch, salt, garlic, and spices) and different percentages (0.5, 1, 1.5 and 2% ) of carrageenan, alginate and xanthan gums. The prepared mixture was kept at 35 °C for 1 hour and then battered and breaded after molding. Physical (expressible water, product yield, and shrinkage), chemical (moisture, fat, and pH), color, texture, and sensory analysis were performed on several samples of shrimp nuggets (containing different percentages of carrageenan, alginate, and xanthan gums) in comparison with the control sample (battered and breaded shrimp immersed in salt and polyphosphate). Results and Discussion Based on the results, the amount of shrinkage decreased in all samples containing gums in comparison with the control (p < 0.05). Shrimp nuggets containing xanthan and alginate showed a lower amount of fat in comparison with the control and the samples containing carrageenan (p < 0.05). The highest amount of pH value observed in the control sample, and the sample containing 1.5 and 2 % alginate showed the lowest amounts of pH. The shrimp nuggets containing 2 % alginate demonstrated the highest amounts of water holding capacity.However, the other samples did not show significant differences with the control (p > 0.05). There were no significant differences between the control and shrimp nuggets containing gums in terms of product yield (p > 0.05). Shrimp nuggets containing 2 % xanthan and the control showed the highest and lowest amounts of brightness, respectively. The highest value of adhesion observed in shrimp nuggets containing 2 % alginate and the control.The lowest amounts of adhesion were observed in shrimp nuggets containing 2 % xanthan, 0.5 % alginate, 1 and 2 % carrageenan (p < 0.05). Samples containing 1% carrageenan showed the highest scores of the sensory attributes of taste, smell, texture and overall acceptance, as same as the control (p ˃ 0.05). Conclusion Hydrocolloid additions were found to be significantly affecting the quality parameters including fat content, pH value, shrinkage and texture of produced shrimp nuggets. Therefore, it seems that producing shrimp nuggets containing 1 % carrageenan showed the nearest physical, chemical, and sensory characteristics to the control (battered and breaded shrimp), and this sample can be used as alternative of battered and breaded shrimp.
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Food Engineering
Fakhreddin Salehi; Moein Inanloodoghouz; Sara Ghazvineh; Parisa Moradkhani
Abstract
IntroductionSour cherries (Prunus cerasus L.) are relatively diverse and broadly distributed around the world, being found in Asia, Europe, and North America. Sour cherries have unique anthocyanin content, and rich in phenolic compounds. The fruits are generally used for processing purposes, such as ...
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IntroductionSour cherries (Prunus cerasus L.) are relatively diverse and broadly distributed around the world, being found in Asia, Europe, and North America. Sour cherries have unique anthocyanin content, and rich in phenolic compounds. The fruits are generally used for processing purposes, such as for production juice and jam. The fruits of sour cherries can also be frozen and dried. One of the best methods for the preservation of agricultural product is drying, which involves removing water from the manufactured goods. Dried sour cherries have a long shelf life and therefore may be a fine alternative to fresh fruit all year round. There are no reports on the effect of microwave pretreatment on the hot air drying kinetics of sour cherries in the literature. Hence, the purpose of this study was to estimate the impacts of microwave pretreatment on the total phenolics, drying time, mass transfer kinetic, effective moisture diffusivity, total color difference index, shrinkage and rehydration of sour cherry. In addition, the moisture ratio changes of sour cherry during drying were modeled. Material and MethodsSour cherries were purchased from the market at Bahar, Hamedan Province, Iran. The average diameter of fresh sour cherries was 1.6 cm. In this study, the water content of fresh and dried sour cherries was calculated using an oven at 103°C for 5 h (Shimaz, Iran). In this research, the effect of microwave time on the drying time, effective moisture diffusivity coefficient and rehydration of sour cherries was investigated and drying kinetics were modeled. To apply the microwave pretreatment on the sour cherries, a microwave oven (Gplus, Model; GMW-M425S.MIS00, Goldiran Industries Co., Iran) was used under atmospheric pressure. In this work, the influence of the microwave pretreatment time at five levels of 0, 30, 60, 90, and 120 s (power=220W) on the cherries was examined. After taking out the treated sour cherries from microwave device, the samples were placed in the hot-air dryer (70°C) as a thin layers. The dehydration kinetics of sour cherries were explained using 7 simplified drying equations. Fick's second law of diffusion using spherical coordinates was used to calculate the moisture diffusivity of sour cherries at various hot-air drying conditions. The rehydration test was conducted with a water bath (R.J42, Pars Azma Co., Iran). Dried sour cherries were weighed and immersed for 30 min in distilled water in a 250 ml glass beaker at 50°C. Results and DiscussionThe results showed that microwave treatment led to an increase in moisture removal rate from the sour cherries, an increase in the effective moisture diffusivity coefficient, and, consequently, a decrease in drying time. By increasing the microwave time from 0 to 12 s, the average drying time of sour cherries in the hot-air dryer was decreased from 370 min to 250 min (p<0.05). The average effective moisture diffusivity coefficient calculated for the samples placed in the hot-air dryer was 4.25×10-10 m2/s. Increasing the microwave time from 0 to 120 s increased the average effective moisture diffusivity coefficient by 85%. The maximum amount of phenolic was related to the sample treated with microwave for 90 seconds. Microwave treatment time had no significant effect on the rehydration of dried sour cherries. ConclusionKinetic modeling of weight changes of sour cherries during drying was carried out using models in the sources, followed the Page model was selected as the best model to predict moisture ratio changes under the selected experimental conditions. The mean values of sum of squares due to error, root mean square error, and r for all samples ranged from 0.001 to 0.007, 0.005 to 0.017, and 0.997 to 0.999, respectively. Generally, 120 s pre-treatment by microwave is the best condition for drying sour cherries.
