Research Article
Food Engineering
Seyed Mohammad Ali Razavi; Morteza Kashaninejad
Abstract
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 ...
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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.
Research Article
Food Technology
Zeinab Mohkami; Hasan Ghorbani Ghouzhdi; Fateme Bidarnamani; Yasub Shiri
Abstract
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 ...
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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).
Research Article
Food Technology
S. Mostafa Sadeghi; Mandana Tayefe; Leili Fadayi Eshkiki; Kambiz Ghiasvand
Abstract
IntroductionBakery 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, ...
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IntroductionBakery 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 MethodsIn 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 DiscussionThe 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. ConclusionConsidering 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 Article
Food Chemistry
Zeinab Ghasemi Arshad; Abdollah Ehtesham Nia; Eisa Hazbavi; Hassan Mumivand; Morteza Soleimani Aghdam
Abstract
IntroductionThe 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 ...
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IntroductionThe 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. ConclusionConsidering 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 Article
Food Technology
Parisa Dianat; Mahdi Haji Abdolrasouli; Morteza Yousefzadi
Abstract
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 ...
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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.
Research Article
Food Technology
Reza Safari; Soheil Reyhani Poul
Abstract
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 ...
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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.
Research Article
Food Biotechnology
Zohre Noruzi Motlagh; Mahmoud A. Mahdavi; Reza Gheshlaghi
Abstract
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 ...
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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 MethodsChlorella 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 ) and three concentrations of phophate (0.01, 0.04, 0.16 ) 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 DiscussionDry weightThe results showed that the highest amount of dry weight was related to the treatment with nitrate amount of 0.25 , 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 increased the growth of microalgae up to 81.8%, so that the dry weight of 0.88 reached 1.6 . However, reduction of nitrate from 0.25 to 0.04 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. CarotenoidsUnlike 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 of nitrate and 0.04 of phosphate (6.7 ).When the nitrate concentration was very low (0.04 ), 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 ), change in phosphate concentration caused a change in pigments concentration. The increase of phosphate concentration from 0.01 to 0.04 increased the carotenoids concentration to 1.65-fold. Of course, increasing phosphate concentration to 0.16 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 . However, phytohormone had no significant effect on dry weight. ConclusionCarotenoid 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 Article
Food Technology
Ali Hosseini; Nafiseh Zamindar; Yasaman Esmaeili
Abstract
IntroductionToday, 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). ...
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IntroductionToday, 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. MethodsEssential 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% alginateT3: 150 ppm Olivieria EOT4: 250 ppm Olivieria EOT5: 1.5% alginate and 150 ppm of Olivieria EOT6: 1.5% alginate and 250 ppm of Olivieria EOAfter 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 CharacteristicsA 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 AnalysisThis 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. ResultThe 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. ConclusionThe 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 Article
Food Chemistry
Iysan Izanloo; Alireza Sadeghi Mahoonak
Abstract
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 ...
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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.
Research Article
Food Technology
Elham Safaei; Hannan Lashkari; Sara Ansari; Alireza Shirazinejad
Abstract
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 ...
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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.
Research Article
Food Engineering
Sima Yassari; Hossein Mirsaeedghazi; Leila Roozbeh Nasiraie; Ali Fadavi
Abstract
IntroductionAs 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 ...
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IntroductionAs 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 MethodsMembrane 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 Article
Food Biotechnology
Masume Atharinia; Nasrin Zonourian; Sare Davarzani
Abstract
IntroductionTomato 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 ...
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IntroductionTomato 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. ConclusionIn 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. AcknowledgementThis 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.
