Full Research Paper
Food Technology
Shokohfeh Taziki; Seyed Mohammad Ali Razavi
Abstract
Introduction Wheat starch granules are composed of amylose and amylopectin, which are responsible for the functions of starch such as swelling, gelatinization, pasting, gel formation, and retrogradation. The retrogradation changes the functional properties, it is an undesirable phenomenon in some ...
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Introduction Wheat starch granules are composed of amylose and amylopectin, which are responsible for the functions of starch such as swelling, gelatinization, pasting, gel formation, and retrogradation. The retrogradation changes the functional properties, it is an undesirable phenomenon in some starch-based foods which reduces the acceptability of food, and shortens the shelf life. Delaying or preventing of starch retrogradation is a major challenge in the food industry. Various ingredients such as carbohydrates imply an important role in improving the functional properties, decreasing amylose leaching and retarding the retrogradation of starch gels. Cress seed gum (CSG), as an emerging galactomannan, has shown the ability to improve the textural and rheological features of food systems based on its unique properties. Addition of CSG to the composite wheat-rice bread increased dough stability and improved the staleness of bread compared to guar gum. Also, the addition of CSG and xanthan gum to gluten-free bread stabilized the texture of bread during storage. Sucrose (SUC) is a common additive in food formulations which is useful as a sweetening agent and textural modification. Sugars have been able to reduce amylose leaching and accelerate or delay starch gel formation. They also delay retrogradation of starch gels during storage. Therefore, the objectives of this study were to determine the impact of different substitution levels of CSG (0, 5, 10 and 15%), SUC (0, 5 and 10%), and their blend on the functional properties (swelling strength and solubility), microstructure features, retrogradation kinetics and synthesis of native wheat starch (NWS) gel (4% w/w).Materials and Methods Cress seeds were purchased from a local medicinal market. NWS and SUC were supplied from Sigma Aldrich (Spain) and Merck (Germany) respectively. Starch suspensions (0.6 gr powder/20 ml water) substituted with CSG (0, 5, 10, and 15% w/w) and SUC (0, 5, and 10% w/w) were prepared to estimate the swelling power and solubility index. To produce starch gel, the 4% w/w suspensions of NWS-CSG-SUC were prepared by dissolving the appropriate amount of CSG powder and SUC in deionized water. Then, each suspension was poured into a stainless-steel cylindrical container and was heated to 95 oC and held at 95 oC for 3 min and then cooled to 50 oC while stirring continuously at 160 rpm with a mechanical mixer. Finally, the pastes were kept at ambient temperature (25 oC) for 1 h. To assess gel structure, imaging of the gels was performed by scanning electron microscopy (SEM). The retrogradation kinetics and syneresis of gel samples were determined after storage at 4 oC for 0, 1, 7 and 14 days.Results and Discussions The swelling power and solubility index of NWS increased with increasing the replacement level of CSG. CSG promotes adhesive interactions among the gelatinized granules. This can enhance the forces applied to them, facilitating water entering (increasing swelling), amylose solubilization and its exudation. In contrast, SUC compete with starch molecules for water in the system and thus preventing gelatinization and mobility of starch molecules reduced the swelling power. The starch-gum-sugar mixtures had a higher swelling power compared to the starch and starch-sugar samples. The mixed samples had higher solubility values than each of them individually. SEM images showed that the pore size of starch gel decreased and increased from 33.01 to 29.44 µm and to 45.37 µm with increasing the substitution levels of CSG and SUC, respectively. NWS-15% CSG-5% SUC gel had 31.34 µm pore size. After storage for 14 days at 4 oC, the CSG substitution with NWS reduced the rate of retrogradation and syneresis from 0.101 to 0.52 (s-1) and from 50% to 23%, respectively. It could be related to creating a film around the granules by the leaked amylose and the CSG in the continuous phase, so inhibiting further swelling and polymers leaking out and related to high water holding capacity of CSG. The addition of SUC reduced the rate of the process to 0.096 (s-1) but because of its low water holding capacity, the value of syneresis enhanced to 57%. In the mixed gels, more reduction of the retrogradation rate and syneresis was observed which was clearly at high CSG replacement. The retrogradation rate of the NWS-15%CSG-5%SUC was 0.057 (s-1) and its syneresis was 45%. According to the results, it can be concluded that 15% CSG and 5% SUC replacement levels can effectively improve the functional properties and reduce the rate of retrogradation and syneresis of NWS during storage.
Full Research Paper
Food Engineering
Elahe Dehghan; Behzad Mohammadi
Abstract
Introduction
Sesame paste is a product that is obtained by mixing Ardeh obtained from peeling of Sesame seeds with sugar or other sweeteners and flavorants such as cardamom and vanilla. Each 100 grams of this nutritious product contains 558 kcal and providing 17% of the daily calcium need, 100% ...
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Introduction
Sesame paste is a product that is obtained by mixing Ardeh obtained from peeling of Sesame seeds with sugar or other sweeteners and flavorants such as cardamom and vanilla. Each 100 grams of this nutritious product contains 558 kcal and providing 17% of the daily calcium need, 100% for iron and 26% for protein. Sesame cream /Ardeh cream provides 478 kcal per 100 grams. Ardeh cream is also a good alternative to chocolates with artificial colors, so it is a very good choice in cases of hypoglycemia, such as before the exam session of students or during heavy excersize such as mountaineering. Sugar substitutes are compounds that, like sugars, are used to sweeten foods, except that they are not digested without the need for metabolized insulin, or are digested sparingly and therefore have little caloric value. The diet products are usually based on reducing calorie intake, which today, the growing interest of people in eating healthy diet has led to an increase in their desire to consume low-calorie products. Patients with diseases caused by sugar consumption such as diabetes, hypertension and hyperlipidemia, osteoporosis, obesity, etc. tend to use artificial sweeteners such as saccharin, aspartame, cyclamate and acesulfame.
Materials and Methods
Hydrogenated oil, Skim milk powder, Whey powder, Soy lecithin, Potassium dichromate, Ethanol, Ardeh , Erythritol, Isomalt Powder, Ribodioside a, Sugar Stable micro histometer systems, Ballmer, Memmert model digital scale, Autoclave, Oven, N Hexane, Desiccator, Soxhlet device, 500 cc balloon, Peptone water, Dichlorine-Rose Bengal Chloramphenicol Agar (DG18), coax reagent, EC broth culture medium, lauryl sulfate culture medium, pH meter with measuring accuracy of 0.1%, 0.1 N sulfuric acid solution, Potassium sulfate, dioxide Selenium, boric acid solution, crystallized copper sulfate, aluminum plate were used in this study . First, to prepare a control sample, raw materials such as flour, oil and sugar were added to the mixer and mixed together, then the rest of the ingredients were added and mixed inside the machine to make the cream uniform and homogeneous. Then it was transferred to the filter and packed in the desired containers. Sugar substitutes were used for the rest of the samples.
Results and Discussion
The prevalence of obesity and diabetes has increased dramatically in recent years, forcing consumers to look for low-calorie sweeteners. Replacing low-calorie sweeteners with sucrose results in low-calorie, and healthy foods. The aim of this study was to present a new formulation using isomalt, ribadioside a, erythritol as sucrose substituents and to investigate its effect on chemical, physical and sensory properties of substituted samples compared to the control sample. The use of sucrose substituents was effective in improving some physicochemical properties of Ardeh so that the moisture content of the substituted samples increased. The results of histological examination also showed that the replaced samples had softer tissue than the control sample, which was due to the weakening of tissue stability by sucrose substitutes. The results of sensory properties based on aroma, taste, odor and texture also showed that sample 2 with the formula 25% sucrose, 6.25% isomalt, 0.003 ribodiozide obtained the highest score in terms of overall acceptance. The reason for the decrease in the general acceptance of the samples replaced with complete elimination of sucrose is the lack of regulation of the desired sweetness by these alternatives. The results of microbial analysis of samples also showed that sugar substitutes have no effect on the microbial properties of Ardeh. According to the obtained results, sample 2 with 25% sucrose, 6.25% isomalt, 0.003% ribodioside a is the best combination and a healthy and low calorie snack.
Full Research Paper
Food Technology
Parisa Shahiri Tabrestani; Mahboobeh Kashiri; Yahya Maghsoudlou; Hoda Shahiri Tabarestani; Mohammad Ghorbani
Abstract
Introduction
There ...
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Introduction
There has been an increasing demand for functional analog meat products due to environmental, human health, and animal welfare concerns. Burger analogs are plant-based products that are designed to mimic the taste, texture, and appearance of meat burgers. They are typically made from a combination of plant-based ingredients such as textured vegetable protein, legumes, grains, and vegetables. The goal of burger analogs is to provide a meat-like experience without using animal-based products.These formulations aim to provide a healthier and sustainable alternative to conventional meat products. The organoleptic properties of burger analogs, including texture, taste, and aroma, are crucial for their acceptance by consumers.
Prickly pear (Opuntia stricta) is a fruit from the Cactaceae family that contains various beneficial components, including natural pigments, proteins, fibers, and polysaccharides. Pectic polysaccharides and arabinogalactans are two types of polysaccharides found in prickly pear that have thickening properties and can improve the texture of food products. Moreover, Prickly pear is a nutritious and functional fruit that can provide various benefits when incorporated into the diet or used as an ingredient in food products. To date, no health benefit analog burgers incorporating Opuntia fruit have been developed.This study investigated the effects of adding Prickly pear pulp powder at levels of 0.5-2.5% on the physicochemical, sensory, and textural properties of analog burgers.
Materials and Methods
Analog burgers were formulated according to Iranian national standards using common ingredients (texturized soy protein, water, canola oil, garlic, dehydrated onion, soy sauce, and guar gum) as a control sample. Mature prickly pear fruits (Opuntia stricta) were collected from west of Mazandaran province in February. The fruits were washed, peeled, and dried in a forced oven dryer at a temperature of 45 °C. The dried samples were then ground into a powder and stored at 4 °C until further physico-chemical parameters of the including moisture, pH, ash, protein, lipid, color and total phenolic content. For developing new formulation of analog burgers, the roasted flour was substituted with prickly pear pulp powder at 0.5%, 1.5%, and 2.5% of the base recipe. The average moisture, ash, fat, carbohydrate content, pH, holding capacity, and color of each raw packed burger were measured. The hardness, springiness, cohesiveness, and chewiness of cooked analog burgers were evaluated using a texturometer instrument. Sensory analysis was performed by 10 panelists who judged discrimination scales of color, odor, taste, and texture characteristics. Analysis and sample treatments were repeated at least three times. Statistical analysis was performed using SPSS (version 19.0), and data were expressed as means ± standard deviation (SD).
Results and Discussion
The lowest and highest cooking losses were observed in analog burgers with 2.5% pulp powder (21.03 ±0.47%) and the control (22.2 ± 0.63%), respectively. However, moisture retention and juiciness did not show significant differences (p > 0.05) between analog burgers with prickly pear pulp powder and the control. The results indicated that increasing prickly pear pulp powder levels significantly decreased the redness (+a*) parameter and yellowness (+b*) of raw analog burgers. Moreover, a reduction in cooking loss and shrinkage were observed for cooked soy burger samples using prickly pear pulp powder. However, cooked analog burgers with added prickly pear pulp powder showed significantly higher juiciness. The elasticity of the produced analog burgers significantly decreased with an increasing percentage of pulp powder (p <0.05).
Conclusion
The incorporation of prickly pear pulp powder in analog burger formulation resulted in a significant decrease in cooking loss and shrinkage of the cooked burgers, while not significantly affecting moisture retention and juiciness. An increase in prickly pear pulp powder levels in analog burger formulation led to a significant decrease in the redness and yellowness of the raw analog burgers, as well as a decrease in their elasticity. Based on the sensory evaluation and consumers' overall tendency to consume burgers, it is recommended to use 1.5% prickly pear pulp powder in analog burger formulation.
Full Research Paper
Food Engineering
Mohammad Khalilian-Movahhed; Mohebbat Mohebbi; Charlotte Sinding
Abstract
IntroductionEfforts have always been made to protect valuable compounds of medicine, food and aromatics materials that are highly sensitive to environmental conditions by the encapsulation method. encapsulation of flavors, in addition to its protection, allows the aromatic substance to be released in ...
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IntroductionEfforts have always been made to protect valuable compounds of medicine, food and aromatics materials that are highly sensitive to environmental conditions by the encapsulation method. encapsulation of flavors, in addition to its protection, allows the aromatic substance to be released in a long time, and the time and place of its release can be controlled. To design these protection systems requires detailed information on encapsulation and release methods, the nature of walls and aromatic materials (Gunning et al.,1999). For encapsulation of sensitive compounds such as lipophilic materials, it is necessary to produce an emulsion of the desired substance in wall materials such as proteins, polysaccharides or a mixture of them. The important factors in encapsulation are the molecular weight, chemical properties and polarity of the core materials, the properties of the materials of the walls, and finally, the methods used to produce microcapsules. (Jafari et al., 2008).The aim of this study was to produce and evaluate the properties of two and six layer multilayer microcapsules containing limonene using soy protein isolate and starch modified by spray drying. The release of encapsulated limonene was investigated under artificial oral conditions under different stress conditions. The results of this study can be used to predict the release rate of the encapsulated flavors and their release conditions.Materials and MethodsSolution preparation: The solution of SPI (0-3%) was prepared by methods of Huang et al. (2012). The OSA starch stock solution (0-2%) was prepared by methods of Nilsson and Bergens (2007).Emulsion’s preparation: the primary emulsion of the optimum SPI and secondary emulsion of optimum OSA starch concentration prepared by the method of Noshad et al (2015).Microcapsule production: To prepare the Microcapsules, a laboratory spray dryer was used. 180±5 ᵒC, inlet air temperature, 25 (ml/min) feed rate, and 90±10 ᵒC outlet air temperature were used. Six layer microcapsules was also prepared in the same conditions (Ansarifar et al., 2017)The micro structure, morphology and release of limonene were evaluated and finally by Zero order, First order, Higuchi, and Korsemeyer- peppas models were used to the fitting of experimental data.Limonene release: To investigate the release of the encapsulated limonene, the release of these microcapsules (two and six layer) at 37 ° C and pH = 6.8, as well as frequent chewing (0, 50 and 100 rpm) were examined. For the apply of shear stress, an oral simulator was designed and developed by the Department of Food Science and Technology of Ferdowsi University of Mashhad was used. Results and DiscusionThe results of particle size changes of the initial emulsion formed with different levels of soy protein isolate showed that the particle size decreased with increasing the concentration of this protein to 1.5% and then it was increased. The results of zeta potential showed that with increasing the concentration of soy protein isolate to 1.5%, the zeta potential of the samples increased and with more than 1.5%, it did not have much effect on the zeta potential of the samples, which indicates that concentrate of 1.5% soy protein isolate has a good ability to cover surface of limonene particles. Similarly, 1.2% of OSA starch was determined for the secondary layer.SEM images of the microcapsules showed that in the two-layer wall microcapsules have cavities, cracks and shrinkage. In the starting of drying, the rate of moisture lost is high and on the other hand, the wall is not strong enough to withstand the stresses caused by the exit of moisture from the walls, so the microcapsule has cavities. In six-layer microcapsules, a smooth, non-cracked surface was observed, which can be attributed to the wall strength due to the increase in the number of layers. Fourier transform infrared spectroscopic (FTIR) test showed that the outer surface of the microcapsules was covered by OSA starch in two and six layer microcapsules.The release profile of encapsulated limonene showed that the release rate in two layer samples was faster than six layer samples. Also, with increasing shear rate, the amount of release increased. The results of experimental models fitting showed that the first-order model had the best description for releasing limonene from two- and six-layer samples in different conditions. Calculation of diffusion coefficient showed that six-layer microcapsules have a lower diffusion coefficient than two-layer microcapsules, which leads to a decrease in the release rate of limonene.Conclusion The results of this study showed that the layer-by-layer method could be used to produce limonene microcapsules. Soy protein isolate and modified starch can cover limonene droplets well. SEM images showed that the structure of six-layer microcapsules is free of cracks and cavities and has a more uniform surface than two-layer microcapsules. To investigate the mechanism of limonene release from two- and six-layer microcapsules, different kinetic models were used to fit the experimental release data. The results showed that the release of these microcapsules occurred based on the diffusion mechanism and Fick's law, which is the main mechanism of mass transfer in the release process. Also, the results showed that the six-layer microcapsules had a lower diffusion coefficient than the two-layer microcapsules and the release rate was lower in the two-layer microcapsule; This is due to the repetitive coating of soy protein isolate and modified starch around the microcapsules and the increase in wall thickness.
Full Research Paper
Food Engineering
Fateme Mousavi Baygi; Arash Koocheki; Behrooz Ghorani; Mohebbat Mohebbi
Abstract
Introduction Curcumin, as a natural polyphenolic nutraceutical has been shown many health-promoting effects, mainly associated with its chemical structure. In various studies, different properties of this compound, including anti-tumor and anti-cancer activity, reduction of blood and liver cholesterol ...
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Introduction Curcumin, as a natural polyphenolic nutraceutical has been shown many health-promoting effects, mainly associated with its chemical structure. In various studies, different properties of this compound, including anti-tumor and anti-cancer activity, reduction of blood and liver cholesterol levels, increase of immune function, prevention of cardiovascular diseases, prevention of damage to biological membranes against peroxidation and anti-inflammatory properties have been reported. Despite possessing a potential health benefits to humans, the susceptibility of this polyphenol towards environmental conditions and low chemical stability has restricted the direct usage of curcumin into aqueous-based food formulations. The encapsulation of curcumin in liposomes is a potentially effective way to protect them from degradation during passing the digestive system.Materials and MethodsCurcumin (powder, purity greater than 99%, 368.38 g/mol), lecithin, cholesterol (C3045-25G), pancreacin (extracted from porcine pancreas, P7545-25G), bile salts (B8756-10G) and calcium chloride (CaCl2) was obtained from Sigma Aldrich (USA). Consumable ethanol was purchased from Pars Ethanol Company (96%, Iran). Lipase enzyme (extracted from pig pancreas, L8070) and pepsin (activity 3500-3000 NFU/g, P8390) were obtained from Solarabio (China). Potassium chloride, dipotassium hydrogen phosphate (K2HPO4) and alpha-amylase enzyme with a purity of at least 99% were obtained from Merck, Germany, sodium chloride (NaCl), sodium bicarbonate (NaHCO3) and calcium chloride were obtained from Sigma. The effect of lecithin content (0.02- 0.08 g), lecithin cholesterol ratio (0.5- 4), curcumin level (1.5- 6mg) and ultrasound treatment time (1-5 minutes) on production of liposomes containing curcumin was evaluated. The particle size, particle size distribution, zeta potential and efficiency were determined by response surface methodology. Furthermore, physical nature, molecular structure, physical stability at 4ºC and 25ºC and release behavior of curcumin loaded-liposome in mouth, stomach and intestines were explored.Results and Discussion The results showed that all independent variables had a significant effect on liposome particle size and increasing the ratio of lecithin: cholesterol caused more uniform particle size. Lecithin was determined to be the only component affecting the zeta potential of liposome particles, and increasing the ultrasound time increased the efficiency of curcumin encapsulation in liposomes. The optimal point of liposome preparation conditions in the amount of 0.08 g lecithin, 4: 1 the ratio of lecithin: cholesterol, 4.16 mg curcumin and 5 minutes the ultrasound treatment was introduced by Design Expert software. In addition, curcumin was amorphous in optimal liposome spherical particles. Furthermore, the results of TEM showed that the liposomes are in the form of single-layer particles, spherical and without membrane rupture. This makes the bilayered nature of the vesicles clearly visible in this micrograph. The size of the particles obtained from this method was consistent with the data obtained from the dynamic light scattering method. From the results of infrared spectroscopy, it can be seen that curcumin is trapped in the liposome through hydrogen bonding in the double-layered vesicle of the liposome, the phenolic ring of curcumin with the phospholipid head group, as well as the hydrophobic interactions of the aromatic rings with the acyl phospholipid chains. Liposomes were more stable at refrigeration temperature. A very small amount of curcumin was released in the simulated oral phase, which is probably due to the short time and lack of specific enzymes to disrupt the phospholipid bilayers of the liposome. Although the pepsin enzyme is unable to penetrate the liposome membrane, acidic conditions change the angle of the head and tail groups of the lipids and lead to a change in the surface charge of the liposomes. The release of curcumin from liposome vesicles was greatly increased in the intestine. This sudden increase is due to the presence of bile salts as an emulsifying agent that can disrupt the phospholipid membrane and make the membrane more fluid. In addition, pancreatic lipase is adsorbed on the surface of lipids and then hydrolyzes the phospholipid into 2-acyl and 1-acyl lysophospholipids and free fatty acids. The release behavior of curcumin under gastrointestinal conditions was based on the Fick mechanism.
Full Research Paper
Food Biotechnology
Ehsan Safari; Hassan Barzegar; Hossein Jooyandeh; Behrooz Alizadeh Behbahani; Mohammad Noshad
Abstract
Introduction
The addition of chemical preservatives increases the shelf life of food products, but prolonged and indiscriminate use of chemical preservatives increases the resistance of microorganisms and the health risks associated with theiruptake. Medicinal plants have a wide variety in the ...
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Introduction
The addition of chemical preservatives increases the shelf life of food products, but prolonged and indiscriminate use of chemical preservatives increases the resistance of microorganisms and the health risks associated with theiruptake. Medicinal plants have a wide variety in the world as well as in Iran. In recent years, the use of natural preservatives such as plant extracts and essential oils, due to their importance and role in controlling the growth of pathogenic microorganisms, has been proposed as an alternative to chemical preservatives. Black pepper is an aromatic medicinal plant. The specific properties of black pepper essential oil, such as its antimicrobial and antioxidant activity, have also been confirmed. Amphotericin B is one of the effective antibiotics for treating infections caused by pathogenic fungi. The mechanism of action of amphotericin B is to destroy fungal cells in such a way that by binding to ergosterol in the cell membrane of fungi, it creates pores and eventually destroys them. One of the most important and common antibiotics used in the treatment of infections caused by pathogenic bacteria is chloramphenicol. This antibiotic is effective against gram-positive and gram-negative bacteria due to its broad spectrum. The aim of this study was to identify bioactive functional groups, antioxidant potential, phenol and total flavonoid compounds and to evaluate the antimicrobial activity of black pepper extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger.
Materials and Methods
In this study, the antimicrobial effect of black pepper aqueous extract was investigated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger by disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. Total phenol and flavonoid contents of the species were determined by Folin-Ciocalteu and AlCl3 assays, respectively. Three biochemical assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis 3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) free radical scavenging and β- caroten/linoleic acid activity systems, were used to evaluate antioxidant activity. Identification of functional groups as well as the structure of organic compounds in black pepper extract was also performed by Fourier transform infrared spectroscopy (FTIR). To evaluate the synergistic effect of black pepper extract in combination with amphotericin B and chloramphenicol antibiotics, Sub-MIC was used.
Results and Discussion
The peaks observed in aqueous black pepper extract confirmed the presence of O-H (3000-3500 cm-1), C-H (2800-3000 cm-1), C=O (1613.62-1633.52 cm-1) and C-O (100.57-1038.82 cm-1) functional groups of bioactive compounds. The total phenol and flavonoids content of the extract were 45.12 mg GAE/g extract and its flavonoid content was 29.66 mg QUE/g extract which had an important role in its antioxidant activity. The aqueous black pepper extract had remarkable DPPH free radical scavenging activity (IC50=32.37 μg/ml), ABTS free radical scavenging activity (IC50=28.45 μg/ml) and beta-carotene bleaching inhibitory effect (46.45%), revealing the electron/hydrogen donating ability of the essential oil. The results of measuring the antimicrobial activity of extract by disk diffusion and agar well showed that black pepper extract showed more antimicrobial effect on gram-positive bacteria Staphylococcus aureus and Bacillus coagulans than gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. This could be due to the difference in their cell wall structure. Aspergillus niger is the most sensitive species to aqueous black pepper extract. The minimum inhibitory concentrations of extract for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger were equal to 32, 16, 4, 8 and 4 mg/ml, respectively. The minimum bactericidal concentration of black pepper extract for two bacterial species, Escherichia coli and Pseudomonas aeruginosa was more than 512 mg/ml. Also, the minimum bactericidal concentration for Staphylococcus aureus and Bacillus coagulans was 128 and 256 mg/ml, respectively, and 128 mg/ml for Aspergillus niger. The results of interaction of black pepper extract with chloramphenicol antibiotic showed that the Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were synergistic, but antagonism was observed for the gram-positive Bacillus coagulans.
Full Research Paper
Food Technology
Masoumeh Shokri; Mostafa Rahmati-Joneidabad; Mokhtar Heidari; Mousa Rasouli; Ahmad Zareh
Abstract
Introduction
Chitosan, as a bio-polymer, has many applications in agriculture. Coating fruits and vegetables with chitosan plays a positive role in increasing their shelf-life, since the chitosan coating reduce growth of fungi and preserves the quality of the fruits longer.
Materials and Methods
This ...
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Introduction
Chitosan, as a bio-polymer, has many applications in agriculture. Coating fruits and vegetables with chitosan plays a positive role in increasing their shelf-life, since the chitosan coating reduce growth of fungi and preserves the quality of the fruits longer.
Materials and Methods
This study was conducted to evaluate the effect of chitosan treatments (0, 0.25, 0.5 and 1%) and storage time (0, 20, 40 and 60 days) on maintaining quantitative and qualitative parameters and shelf life of grape fruit of Fakhri cultivar. The experiments were factorial based on a completely randomized design with three replications. The fruits were stored for 2 months. Some characteristics of fruits including percentage of weight loss, percentage of berries abscission, percentage of decay of berries, browning of berries and biochemical characteristics including titratable acidity, ascorbic acid content, total phenol, enzymes activity including peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) were measured in order to investigate the best treatment.
Results and Discussion
The results showed that the traits under study were affected by different concentrations of chitosan, with the lowest percentage of weight loss associated with the concentration of 0.5% chitosan. Chitosan, by forming a semi-permeable membrane, regulates gases,and reduces the transfer of water from fruit tissues. The lowest amount of browning of berries was observed in the concentration of 0.5% chitosan. Chitosan is partly prevented from increasing the activity of brown-peroxidase in chitosan-treated fruits. There was no significant difference in concentration of 0.5% chitosan with 1% concentration. The lowest percentage of contamination and percentage of berries abscission was observed in 1% chitosan concentration. It seems that these treatments prevent the effects of ethylene levels and the formation of a swab layer at the site of fruit attachment to the cluster. The slightest increase in the titratable acidity and the lowest decrease of ascorbic acid was observed in the concentration of 1% chitosan. Higher levels of ascorbic acid in fruits that are coated with chitosan may be due to decreased oxygen levels and respiration inhibition. The highest total phenol was related to the control treatment, which may be due to the loss of chlorophyll and the onset of synthesis of phenolic compounds. The highest level of activity of PAL enzyme was observed in the concentration of 0.5% chitosan and the control. This enzyme is stimulated by various live and non-living stresses. In general, the highest activity of peroxidase enzyme was observed in the concentration of 0.5% chitosan and the highest activity of polyphenol oxidase in 1% concentration of chitosan.
Conclusion
It seems that the concentration of 1% chitosan can improve the quality of fruits for a longer time while increasing the shelf life of fruit.
Full Research Paper
Food Technology
Mahya Hosseinzadeh; Mohammadyar Hosseini; Mohammad Shahedi; Mehdi Kadivar
Abstract
Introduction
The most important component of wheat proteins is gluten, and the most prominent bonds in gluten are disulfide bonds, which bind glutenin subunits. Therefore, oxidizing and reducing agents with great effects on the thiol-disulfide system of the dough can change the mechanical and rheological ...
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Introduction
The most important component of wheat proteins is gluten, and the most prominent bonds in gluten are disulfide bonds, which bind glutenin subunits. Therefore, oxidizing and reducing agents with great effects on the thiol-disulfide system of the dough can change the mechanical and rheological properties of the dough. Due to the positive effects of ascorbic acid on the properties of the dough, it is used as a flour improver. To weaken the structure of the dough, reducing agents such as cysteine-L can be used, and by adding organic acids, increasing the specific volume and decreasing the moisture, the pH and hardness are observed in comparison with the control. This study is performed to evaluate the effect of adding reducing compounds, vitamin C and organic acids during the conditioning of wheat and their effect on the yield of the resulting pulp.
Materials and Methods
First, Physical properties of wheat include: specific density, colorimetry, estimation of grain length, width and thickness, grain hardness, hectoliters, 1000-grain weight, grain moisture, degree of extraction were measured for the tested wheat. Moisture, pH, ash, particle size, fat, protein and zeal number tests were performed on wheat flour. From elementary cleaned and weighed wheat, 13 samples of 240 g each were weighed separately and poured into plastic bottles. One sample was conditioned with only 30 ml of distilled water and the other 12 samples were conditioned with the following solutions, respectively:
1- Cysteine solution at three levels of 0.25, 0.5 and 0.75% by weight
2- Citric acid solution in three levels of 0.3, 0.4 and 0.5% by weight
Vitamin C solution in three levels of 100, 150 and 200 ppm
4- solution of 80 ppm vitamin C and 0.1% cysteine, solution of 100 ppm vitamin C and 0.2% cysteine, solution of 120 ppm vitamin C and 0.3% cysteine
After 24 hours, the conditioned wheat samples were milled by a laboratory waltz mill, and then subsequent tests including gluten, sulfhydryl-disulfide, glutathione, and solvent retention capacity (SRC) were performed on the samples.
Statistical analysis was performed using SAS statistical software in a randomized complete block design. Each measurement was performed in at least three replications and the means were compared at 95% confidence level with the least significant difference in LSD.
Results and Discussion
The results of physical tests on wheat grain and chemical tests on flour obtained by milling the wheat samples without adding additives during conditioning are presented in tables. The results of gluten, glutathione, sulfhydryl-disulfide and solvent storage capacity tests on samples of conditioned wheat flours are also presented. Based on the results of gluten and glutathione test, it was shown that ascorbic acid is oxidizing and strengthening the dough, but cysteine is reducing and weakening the dough. Simultaneous addition of cysteine and ascorbic acid strengthened the dough, adding citric acid to certain level strengthened the dough as exhibited in the gluten test. However, byond that level, weakened the dough, but in the glutathione test it was almost ineffective. The results of sulfhydryl-disulfide test showed that increasing the amount of vitamin C at three levels of 100, 150 and 200 ppm increases the number of disulfide bonds, although this increase was not in linear trend, which can be due to the limited number of groups of sulfhydryl with a suitable spatial arrangement for oxidation. Accordingly, the number of sulfhydryl groups is significantly reduced, although it does not reach zero. With the addition of reducing cysteine, the opposite trend was the case, as the number of thiol groups increased, the number of disulfide bonds and bridges decreased. The addition of organic acid had no significant effect on both parameters and showed that the performance of these two variables is independent. By adding both reducing and oxidizing compounds, it was found that the oxidizing effect of vitamin C is far greater than the reducing effect of cysteine. Regarding the solvent retention capacity test performed with 4 solvents of deionized water, 50% sucrose, 5% sodium carbonate and 5% lactic acid, the expected results are that the addition of cysteine has a reducing and weakening effect on the dough, adding vitamin C and cysteine + vitamin C strengthens the dough and the addition of citric acid initially strengthens the dough, but by increasing its level weakens the dough, but this effect is small and can beneglected . The results obtained by comparing the samples conditioned with cysteine, vitamin C, citric acid and cysteine + vitamin C, with the sample conditioned with distilled water in some additive levels matched the expected results, but in some cases did not.
Full Research Paper
Food Technology
Fariba Hadidi; Ali Ganjloo; Mohammad Hadi Fakoor
Abstract
Introduction
The demand for non-dairy and reduced-calorie products has increased substantially for several reasons. Almond (Prunus dulcis) milk is highly appreciated by lactose-intolerant, hypertensive people and celiac patients whom are not able to consume animal's milk. Thus, the development ...
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Introduction
The demand for non-dairy and reduced-calorie products has increased substantially for several reasons. Almond (Prunus dulcis) milk is highly appreciated by lactose-intolerant, hypertensive people and celiac patients whom are not able to consume animal's milk. Thus, the development of various non-dairy products is essential. Desserts are the most common and popular product containing high amount of fat and sucrose. The consumption of sucrose is restricted for diabetic people due to its high glycemic index. Stevia as a low-calorie sweetener is one of the sucrose substitutes in food products. Sucrose substitutes must mimic the techno-functional properties of sucrose. Generally, commercially available sucrose substitutes do not possess all of the required characteristics. Therefore, using them in blend form with sucrose is suggested. Moreover, sucrose replacement especially in desserts generates a negative effect due to low firmness or higher syneresis. In this regard, hydrocolloids can be used to overcome those drawbacks. Therefore, the current study was carried out to investigate and optimize the non-dairy dessert formulation based on almond milk containing Tragacanth gum and stevia. For this purpose, the effect of Tragacanth gum and stevia as a sucrose replacer on the physicochemical properties such as hardness, viscosity, color coordinates including lightness, redness-greenness (a*), yellowness-blueness (b*), total soluble solids and syneresis was evaluated and optimized using Response Surface Methodology (RSM).
Materials and Methods
All of the materials used for the manufacturing of non-dairy dessert including raw almond, stevia and Tragacanth gum were purchased from a local market of Zanjan, Iran. For the production of non-dairy dessert, the almond milk warmed up to 40 ºC and then stevia as a sucrose substitutes and tragacanth gum powder as a stabilizer were added in the ranges of 25-75% and 0.4-1% w/w, respectively. Later, the temperature of the mixture increased to 72 ºC and kept for 10 min and then, the temperature decreased to 42 ºC to inoculate the starter culture (a mixture of Streptococcus thermophilus and Lactobacillus bulgaricus, 2% w/w). The fermentation process was completed at 37 °C for 24 h. Finally, the temperature of non-dairy dessert based on almond milk was decreased to 4ºC and kept at the same temperature until further analysis. The pH of the desserts was measured using a pH meter model AZ 86502 (AZ, Taiwan). Total soluble of the desserts was determined using a refractometer (ATAGO, Japan). Firmness was determined using a STM-5 texture analyzer (SANTAM Co., Iran) equipped with a 20 Kg load cell and 10 mm probe. Viscosity was measured using a programmable Viscometer (R/S-CPS+, Brookfield, USA) equipped with a cone-plate geometry at shear rate of 100 s−1. Instrumental color measurement was carried out by a handheld colorimeter (TES135-A, Taiwan) considering L*, a* and b* as color coordinates. Syneresis was measured by a centrifugation test. Fifteen semi-trained panelists (7 male and 8 female) were selected to evaluate sensory properties of the control (only contains sucrose) and optimized formulation samples for texture, color, appearance, taste, flavor, total acceptance using a 5-point Hedonic scale (1= dislike extremely and 5=like extremely). The RSM-central composite design was used to build up the experimental design and identify the conditions that yield highest firmness, viscosity, L*, and total soluble solids as well as lowest a*, b* and syneresis.
Results and Discussion
The results obtained revealed that the hardness, viscosity, a* and total soluble solids increased significantly (p<0.05) while the lightness, b* and syneresis decreased significantly (p<0.05) with increasing the Tragacanth gum in the formulation of non-dairy dessert based on almond milk. In addition, increasing the replacement of sucrose with stevia significantly (p<0.05) reduced the hardness, viscosity, total soluble solids, and increasing lightness and syneresis. However, increasing the percentage of sucrose replacement with stevia had no significant effect (p>0.05) on the changes of a* and b*. Optimization of non-dairy dessert formulation based on almond milk was carried out using numerical technique. The optimal formula was 1% Tragacanth gum and 45% replacement of sucrose with stevia. Under these conditions, hardness 0.08 N, viscosity 1.20 Pa.s, lightness 82.77, redness-greenness 0.95, yellowness-blueness 5.60, total soluble solids 8.29 ºBrix and syneresis 11.88% were obtained. The results of sensory evaluation showed that addition of Tragacanth gum and replacing stevia at the optimal levels improved the total acceptance score compared to the control sample.
It can be concluded that in addition to the reliability of the RSM to select the optimal formulation conditions, Tragacanth gum and stevia can be used to produce a new, reduced-calorie and customer-friendly non-dairy dessert based on almond milk.
Full Research Paper
Food Engineering
Ali Heydari; Masoud Goharimanesh; Mohammadreza Gharib; Ali Koochi
Abstract
Introduction
The beneficial use of ultrasonic systems has been proven in many applications. Among them, ultrasonic atomization is widely used in various industries, including food and coating industries. Ultrasonic vibrations of liquids can produce fine droplets called atomized fluid. During the fluid ...
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Introduction
The beneficial use of ultrasonic systems has been proven in many applications. Among them, ultrasonic atomization is widely used in various industries, including food and coating industries. Ultrasonic vibrations of liquids can produce fine droplets called atomized fluid. During the fluid atomization process, droplet size and distribution can be precisely controlled so that the droplets become very small and high-level particle distribution is achieved which can be easily evaporated. This method is widely used in various industries, including food industry (for the production of driedpowder products) and coating industry. The key factor that affects droplet size is the frequency and amplitude of the ultrasonic vibrations and the properties of the fluid, including the fluid viscosity and surface tension.
Materials and Methods
Based on a review of literature, it is clear that the modeling of the ultrasonic method for spray dryers and the production of milk powder has not been done so far. In the present work, first, the research background is reviewed and then, using the relationships provided for the ultrasonic atomization of different fluids in the reviewed articles, the effect of ultrasonic vibrations on the atomization and evaporation of milk as a food and the powder production was studied using spray drying process. Then the effects of various oscillation parameters such as frequency, amplitude and also the temperature of the fluid, which affects its viscosity, density and surface tension, on the rate of atomization of the fluid was investigated. In the present work, we first examine the fluid whose range of properties is true in relations. One of the most widely used liquids in the food industry is milk. By examining the viscosity, surface tension and density of the milk and obtaining the dimensionless numbers We, In and Oh, it is determined that the provided relations can also be used for milk. After calculating the diameter of the evaporated particles of milk due to ultrasonic vibrations as well as the evaporation rate, the independent variables of the research can be changed. First, in the constant physical properties of a fluid, we change the frequency and amplitude of ultrasonic oscillations and studied their effect on the produced particle diameter and evaporation rate. In the next step, with the constant frequency and amplitude of ultrasonic oscillations, the effect of changes in fluid properties (temperature change) on the produced particle diameter and evaporation rate was investigated. In the next stepthe effect of frequency and amplitude of ultrasonic fluctuations as well as changes in fluid properties (temperature change) on the powder diameter produced and the time required for the drying process was investigated. The analysis of all data obtained from the above steps was performed using Mathlab software.
Results and Discussion
The main and summary results obtained from the present study are as follows:
As the amplitude of the vibrations and the temperature of the milk increased, the drying time required for the evaporation of droplets decreased, but the powder diameter and the evaporation rate increased.
As the frequency of vibrations increased, the drying time required for the evaporation of droplets increased, but the powder diameter and the evaporation rate decreased.
The results showed that quadrupling the amplitude of the vibrations reduces the time required for the droplets to dry by 14.4% and increases the evaporation rate by 62.6%. At a constant temperature of the gas dryer and the milk, changing the frequency from 10 to 40 kHz results in 21.4% increase in the time required for the droplets to dry. Also, with increasing the temperature of the milk from 15 to 30°C, at a constant frequency and amplitude of vibrations, the time required for drying the droplets decreases by 12.4% and the diameter of the particles produced increases by 11.3%.
Conclusion
In this research, the process of ultrasonic assisted evaporation of whole milk and drying and production of milk powder has been modeled mathematically and thermodynamically. The calculation code was written using Mathlab software and after making sure that the solution conditions are in the desired range of equations, the results were presented. In the present work, the effect of the frequency and amplitude of ultrasonic vibrations as well as the initial temperature of milk on the diameter of the evaporated particles, the evaporation rate, the diameter of the powder produced and the time required for the evaporated droplets to dry by ultrasonic method was investigated.
Full Research Paper
Food Technology
Masoumeh Salamatian; Younes Zahedi; Rezvan Shaddel
Abstract
Introduction
Capparis spinosa is a perennial herb from the Capparidaceae family that is mainly distributed in arid and semi-arid regions. Its fruits are oval shaped, approximately 3 cm long, greenish in color with red pulp. Capparis spinosa extract is a rich source of phenolic compounds. The instability ...
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Introduction
Capparis spinosa is a perennial herb from the Capparidaceae family that is mainly distributed in arid and semi-arid regions. Its fruits are oval shaped, approximately 3 cm long, greenish in color with red pulp. Capparis spinosa extract is a rich source of phenolic compounds. The instability of phenolic compounds in the environmental conditions as well as their bitter or astringent taste has created challenges for the use of these compounds in the food industry. Encapsulation is a method that can positively affect bioaccessibility and bioavailability as it ensures the coating of the active component and its targeted delivery to a specific part of the digestive tract and controlled release. Encapsulation using nanoliposomes seems to be an appropriate technique to overcome these issues. Nanoliposomes are the nanometric version of liposomes. Liposomes are spherical particles composed of lipid molecules (mainly phospholipids) that tend to accumulate in polar solvents such as water in the form of bilayer membranes. Encapsulation with liposomes is an effective way to preserve the intrinsic properties of bioactive compounds during storage and production of foods fortified with them, as well as a physicochemical barrier against prooxidant agents such as free radicals, oxygen and UV.
Materials and Methods
Materials: Capparis spinosa fruits, were collected from subtropical regions of Ilam province (Iran). Folin ciocalteu, gallic acid and tween 80 from Merck (Germany), cholesterol and phosphatidylcholine from Sigma- Aldrich (Germany) were obtained.
Methods: The extract was obtained from capparis spinosa fruit powder using ultrasonic bath (Backer, vCLEAN 1- L6, Iran). The phenolic content was measured by folin ciocalteu method. Nanoliposomes containing capparis spinosa extract were prepared in ratios of 60- 0, 50- 10, 40- 20 and 30- 30 w/w lecithin- cholesterol. Then, particle size, PI and zeta potential were measured by DLS (Horiba, Japan) at 25 oC. After calculating the encapsulation efficiency using its corresponding equation, the investigation of possible reactions between capparis spinosa extract and phospholipids was performed using FTIR at a frequency of 400- 4000 cm-1. In order to observe shape and morphology of nanoliposomes loaded with capparis spinosa extract by field emission scanning electron microscopy (FESEM), a drop of sample was poured on the laboratory slide, dried at ambient temperature and then, the sample was coated with gold layer using an ion sputtering device. The stability of the samples was evaluated by visual observation of phase separation and the release rate of phenolic compounds encapsulated in nanoliposomes at ambient temperature over a period of 60 days.
Results and Discussion
The amount of phenolic extract was 6.328 mg of GAE/g dry sample. The average particle size (Z- Average) was in the range of 95.05 to 164.25 nm. Increasing the cholesterol concentration resulted in enhancement of particle size of nanoliposomes. The particle size distribution was in an acceptable range of 0.3 to 0.5 (PI 0.5). The PI of the cholesterol-free nanoliposomes was maximum and significantly higher than that of the others. Addition of cholesterol increased zeta potential from -60.40 to -68.55. Higher zeta potential values indicate a higher and long term stability of the particles. Also, cholesterol led to an increase of encapsulation efficiency (EE). The stability of phenolic compounds loaded in nanoliposomes was affected by cholesterol during storage time via reducing fluidity and permeability of liposomal membrane. Presence of cholesterol also inhibited the membrane rupture and any changes into it. Results of FTIR showed interactions between wall constituents of nanoliposome and capparis spinosa extract, and confirmed successful loading of the extract within nanoliposomes. Images of FESEM were in agreement with DLS results regarding particle size and particle size distribution.
Conclusion
This study indicate that the nanoliposomes have potential applications in improvement of the shelf life of nutraceuticals, stability of cosmetic materials and drug delivery systems. The phenolic compounds of encapsulated extract showed good stability within two months of storage at room temperature. The results showed that the problem of instability of phenolic compounds, which leads to their limited commercial application, can be solved by encapsulation.
Full Research Paper
Food Chemistry
Maryam Rahimipanah; Alireza Sadeghi Mahoonak; Mohammad Ghorbani; Hoda Shahiri Tabarestani; Mohsen Nabimeybodi
Abstract
Introduction
High levels of free radicals can damage biomolecules and eventually cause oxidative stress. Bioactive peptides produced during enzymatic hydrolysis keep high health properties, such as antioxidant properties. The production of antioxidant peptides has received much attention as a ...
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Introduction
High levels of free radicals can damage biomolecules and eventually cause oxidative stress. Bioactive peptides produced during enzymatic hydrolysis keep high health properties, such as antioxidant properties. The production of antioxidant peptides has received much attention as a new generation of natural antioxidants. Plants are one of the most abundant sources of biopolymers, especially protein. As long as the protein structure is intact, its amino acid sequence is inactive; however, during proteolysis, fermentation, and gastrointestinal digestion, these amino acids are released as oligopeptides ordinally with less than 20 amino acids and below 10 kDa in molecular weight. These peptides are more digestible and can exhibit specific bioactive properties such antioxidant properties. In this regard, the use of food waste containing protein to produce bioactive peptides and increase their value has received increasing attention. Enzymatic hydrolysis can increase their functional properties by converting proteins into peptides without affecting their nutritional value. Pomegranate seed protein is a by-product of the pomegranate seed oil industry and can be a good source of bioactive peptides with antioxidant properties. According to our knowledge, there isn’t any data about the enzymatic hydrolysis of pomegranate seed protein for antioxidant peptides production. In this study, the optimal conditions for enzymatic hydrolysis of pomegranate seed protein with trypsin using the responses surface method and the effect of hydrolysis on protein structure were investigated.
Materials and Methods
In this study, the protein was extracted from pomegranate seed, and using trypsin the optimization of enzymatic hydrolysis conditions of protein was determined by Face-Centered Central Composite design, which is one of the responses surface design methods. The effect of independent variables including temperature (30 to 45 °C), time (30 to 180 minutes), and enzyme to substrate ratio (1 to 3 w/w) on DPPH free radical scavenging activity and Fe+3 reducing power as responses, was evaluated. Validation tests were performed for confirmation of the proposed values by software and the degree of hydrolysis of the samples was determined. In the next step, the unhydrolyzed and hydrolyzed protein was evaluated for molecular weight distribution and their surface hydrophobicity was compared. Finally, scanning electron microscopy images were used to confirm the hydrolysis process.
Results and Discussion
Under optimal conditions obtained from the response surface method (temperature: 37.6 °C, time: 136.55 minutes, and enzyme to substrate ratio: 2.2%), trypsin-derived hydrolyzate, showed DPPH free radical scavenging power: 87±0.89% and Fe+3 reduction power: 0.293±0.44. Under these conditions, the degree of hydrolysis was equal to 30.1±1%. The optimum conditions of hydrolysis were validated by RSM. The increase in the surface hydrophobicity of the protein after the hydrolysis process indicated the unfolding of the pomegranate seed protein chain and the exposure of its structure during the reaction. The electrophoretic profile of denatured pomegranate seed protein showed smaller peptide bands and lower band intensity, along with losing some of the peptide fractions after hydrolysis. so the efficacy of trypsin at cleaving the protein was confirmed. Evaluation of images obtained by scanning electron microscopy showed that unhydrolyzed protein had complex structures comprised of random sheets of different sizes and shapes and the protein degraded into small fragments and looser structure with many folds after enzyme hydrolysis, resulting in smaller particles compared with untreated samples with the same SEM parameters
Conclusion
Considering the consumer’s tendency toward functional foods and present concerns about the application of synthetic additives and according to the results, the hydrolyzed pomegranate seed protein prepared by trypsin shows good antioxidant capacity. In addition, there will be a reduction in waste generated by the pomegranate processing industry. Further studies will need for the isolation and identification of the specific peptides and amino acid sequences and the evaluation of their possible incorporation in food matrices.
