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Abstract The aim of this study was to hydrolysis of rainbow trout viscera by application of flavourzyme, papain and pepsin enzymes and compare the functional and antioxidant properties of these three types of proteins. At the same time, the maximum degree of hydrolysis and nitrogen recovery was recorded for the hydrolysate produced by flavourzyme (23.12 ± 1.05% and 55.64 ± 0.68% respectively). In all pH values tested (apart pH 8 and 10), hydrolysate produced by flavourzyme showed the highest solubility compared to other proteins (p<0.05). In addition, emulsion activity (apart from pH 4) and emulsion stability index (apart from pH 8) in this protein were higher in comparison with two other proteins (p<0.05). To compare the antioxidant properties of hydrolysate, the inhibition capability of scavenging of 2,2 diphynyl-1-picrylhydrazyl (DPPH) free radicals and reduction capacity of iron (III), were measured. As a result, hydrolysate produced by pepsin showed highest DPPH scavenging power (83.59 ± 2.27 %) and iron (III) reduction power (0.886 ± 0.013 absorbtion in 700 nm).This study showed that the proteins produced from the substrate has favorable properties and various factors, including the type of enzyme used greatly affect these properties.

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The purpose of this study is to evaluate the purchase amount of shrimp in the market and the relationship between consumption amount and some of demographic characteristics. The statistical population of this study is the whole country that 10 cities including Mashhad, Tehran, Tabriz, Birjand, Kermanshah, Gorgan, Yazd, Bandar Abbas, Ilam and Shiraz were randomly selected and a total 1000 questionnaires were completed by citizens proportionate to the household population of the studied cities. In order to evaluate the number of shrimp purchases per year as well as the amount of each purchase, from the output of SPSS software and to investigate the existence of a significant relationship between consumption amount and demographic characteristics, correlation tests were used. According to the results the number of times shrimp were bought by the household varied from one to twelve times a year (average 1.71±1.11). 44.2% of households of the consumption society bought shrimp once a year and 28.6% of them bought shrimp twice a year. It was further found that the amount of shrimp purchased by household varies from 0.5 to 2 kg per purchase (average 0.92±0.26 kg). while 76.3% of households of the consumption society purchase one kilogram of shrimp in per purchase. According to the findings, consumption amount had no significant relationship with the age, job and field of study variables (p>0.05). But the relationship between this index with the education level and number of household members variables was significant (p<0.05).  

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Despite the high nutritional value of shrimp, its per capita consumption in the country is low. Therefore, it is necessary to investigate the reasons for this shortage and to propose ways to increase per capita consumption in order to maintain the health of the population. To this purpose, the behavior of shrimp consumers must first be evaluated. This study was conducted to evaluate the behavior of shrimp consumers in the country by using the general framework of the theory of planned behavior. The statistical population of the study was the whole country which selected 10 cities (Mashhad, Tehran, Gorgan, Bandar Abbas, Yazd, Shiraz, Kermanshah, Ilam, Birjand and Tabriz) by randomized sampling and completed 1000 questionnaires by citizens. Statistical analysis were performed using the Structural Equation Model and Liserl software. The results showed that attitude, subjective norm and perceived behavior control had a positive and significant effect on the intention to shrimp consumption. In addition, the perceived behavior control was also effective on increasing of shrimp consumption. It was found that only two assumptions about the significant effect of convenience of cooking on the attitude and the significant effect of income on the subjective norm were rejected and other assumptions (significant effect of quality, packaging and type of supply and processing on attitude, significant effect of price and positive and negative beliefs on subjective norm, significant effect of consumption time, availability and experimental records on perceived behavior control and significant effect of intention to consumption on increasing of shrimp consumption) were confirmed.

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In order to increase the per capita consumption of shrimp in Tehran and its proper placement in the household food basket, it is necessary to study the factors affecting the attitude of citizens towards shrimp consumption as well as the factors affecting on decision to purchase. The purpose of this applied-research study also is to investigate and evaluate these factors. For this purpose, by studying internal and external sources, a number of factors affecting consumers' attitudes and their decision to purchase were identified and then tested in the form of assumptions in the target population. The statistical population of the study is the whole city of Tehran which randomly were selected 12 municipal districts for field study with sample size of 500 people. To collect data, a questionnaire was designed according to the assumptions and completed by the consumption society. In order to test the assumptions and investigate the severity and direction of the relationship between their items, a conceptual model was designed and evaluated by structural equation modeling (Lisrel software). In testing hypothetical factors affecting citizens' attitudes were found quality, type of supply and processing, packaging and different beliefs have positive and significant effects on people's attitudes. But the convenience of cooking of shrimp as well as the time and place of consumption had no significant effect on the attitude of citizens. In the following, the results showed that experimental records of consumption, income and price of shrimp are effective on the intention to purchase but the access factor does not have a significant effect on the intention to buy shrimp. Values of effect coefficients showed that among the effective factors on attitude of citizens and the decision to buy, quality and experimental records of consumption are the most effective factors, respectively.

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Given the concerns regarding the use of synthetic antioxidants in the food industry, it seems necessary to identify and use substances containing natural antioxidants. Protein-containing wastes are one of these substances from which antioxidant compounds can be extracted in various ways. The aim of this study was to compare and comprehensively evaluate the antioxidant activity of bioactive peptides produced from three sources of waste including fish (FPH), poultry (PPH) and shrimp (SPH) with flavourzyme enzyme. Therefore, post-production bioactive peptides from these three sources were compared in term of all common and uncommon antioxidant tests in the food industry. The results showed that the peptides produced from these three sources (with the same enzyme and degree of hydrolysis) were different in terms of antioxidant activity. In free radical scavenging activity tests of DPPH and ABTS, linoleic acid peroxidation inhibition and metal chelating power, SPH was significantly higher than the other two proteins (p<0.05). The values of these four indices in SPH were measured 87.45±1.38%, 79.26±0.59%, 94.56±1.62%, and 71.49±0.37 %, respectively. There was no significant difference between SPH and FPH regarding ferric ion reducing power and hydroxyl free radical scavenging activity (p>0.05). Also, FPH and PPH did not show significant differences in terms of ABTS free radical scavenging activity index (69.15±0.85% and 68.44±1.93% respectively). In general, based on the results of the tests, in the present study, bioactive peptides produced from shrimp wastes (SPH) had the highest antioxidant activity. Peptides from fish wastes hydrolysis (FPH) was ranked second. In almost all tests, the lowest antioxidant activity was related to poultry wastes peptides (PPH).

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The aim of this study was to produce biological silage from chicken waste based on fermentation of autogenous bacteria and to evaluate the quality characteristics of the product. In order to produce this product, sampling was performed from selected slaughterhouses in Mazandaran province and biosilage was produced in the form of a one-ton fermenter using autogenous bacteria isolated from the region (fermentation). The final product (dried biosilage powder) was evaluated qualitatively using standard methods and compared with other sources including meat powder, blood powder and kilka fish powder (produced by batch method). The results showed that the amount of protein, fat and protein digestibility in the produced biosilage was 59.09%, 21.30% and 87.41%, respectively. The product produced was in a better condition than meat powder and kilka fish powder in terms of the mentioned indicators. The produced biosilage did not show a significant difference between blood powder in terms of calcium and phosphorus and was at a lower level than kilka fish powder and meat powder. The levels of TVN, PV and TBA in biosilage were measured as 46.56, 4.46 and 2.21, respectively. These indices are in a much more favorable condition in the produced product compared to Kilka meat powder and fish powder. It was further found that the microbial parameters (mold, yeast, coliform, fecal coliform, E.coli) in the samples of meat powder, blood powder and kilka fish powder were relatively higher compared to biosilage of chicken waste. According to the results of the present study, chicken waste has the ability to be converted into biosilage with desirable characteristics that can be used in agriculture and aquaculture industries.

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Due to the concerns about the use of artificial colors in various foods, it is necessary to pay attention to sources with natural colors. One of these sources is the algae Spirulina, which contains the blue pigment phycocyanin. The aim of the present study in the first stage was to extract this pigment from the algae by enzymatic method and its nanoencapsulation. In the second stage, the physicochemical properties of nanoparticles were investigated. Finally, phycocyanin in both free and nano forms was added to the ice cream formulation and the qualitative and sensory properties of the product were evaluated in comparison with the control. The results showed that the produced nanoparticles have an average size of 397.1 nm. The encapsulation efficiency of the process was recorded 73.41%. According to the images recorded using scanning electron microscopy, the nanoparticle with different dimensions are scattered in the microscopic spread so that the particles are visible in different sizes. The release results of nanoparticles in vitro showed that at pH=1.2, the release percentage of phycocyanin is low (the first 2 hours). So that it fluctuates in the range of 7 to 13%. But after this stage (pH=7.4), the release rate increased significantly and from 35 to 71% at 3 and 4 hours, respectively. The use of pure phycocyanin in ice cream formulation improved the hardness, melting percentage, texture, hardness, crystalline intensity and coldness. But these indices were reported at a more favorable level in the treatment formulated with nanoencapsulated phycocyanin. The color index in ice cream formulated with pure phycocyanin was more desirable and more acceptable compared to the treatment with nanoencapsulated phycocyanin. Due to the properties of phycocyanin, especially the nanoencapsulated form, it can be used as a biological dye and improver the quality and sensory properties in various ice creams.

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Following the concerns created in the field of using synthetic preservatives in various foods, it seems necessary to pay attention to natural compounds with preservative properties. Phycocyanin extracted from spirulina microalgae is one of these compounds. The aim of the present study was to extract (using enzymatic method) and nanoencapsulation of this pigment with maltodextrin-sodium caseinate combination coating and evaluate the antioxidant and antibacterial activity (against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Yersinia ruckeri and Streptococcus iniae) of nanocapsules in comparison with pure phycocyanin. The results showed that with increasing the concentration of phycocyanin (in both pure and nanoencapsulated forms), the antioxidant and antibacterial activity of the treatments increased significantly (p<0.05). Comparison of the properties of the treatments on days 0 and 60 (stored at -18°C) showed that the antioxidant and antibacterial activity of pure phycocyanin was significantly reduced over time (p<0.05). But the nanoencapsulation technique prevents the mentioned properties from changing and helps to preserve them. Among gram-positive bacteria, Listeria monocytogenes was more sensitive than the other two bacteria and all concentrations used had an inhibitory effect on this bacteri. Staphylococcus aureus was resistant to two concentrations of 2.5 and 5 μg/ml and Streptococcus iniae to three concentrations of 2.5, 5 and 10 μg/ml. Among the two gram-negative bacteria, Yersinia ruckeri was more sensitive and the concentrations used, with the exception of concentrations of 2.5 and 5 μg/ml, had an inhibitory effect on both bacteria. According to the results of the dilution method, for the studied bacteria, the MIC range was between 50-500 and the MBC between 100-500 μg/ml. Also, the lowest MIC was recorded for Listeria monocytogenes and the highest MBC was recorded for Streptococcus iniae. It can be concluded from this research that first, pure phycocyanin has antioxidant and antibacterial activity; second, nanoencapsulation of this pigment with combined coating of maltodextrin-sodium caseinate improves these properties and their stability during the storage period.
 

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In the present research, after extracting astaxanthin from Haematococcus microalgae and nanoencapsulation it with maltodextrin-sodium caseinate combination coating, carrier nanocapsules with different ratios replaced sodium nitrite (limit of 120 mg/kg) in the sausage formulation. Then, the microbial (Count of mesophilic, psychrophilic, enterobacteriaceae, lactic acid and pseudomonas bacteria) and tissue properties of the formulated sausages were evaluated and compared during the storage period (28 days at refrigerator temperature). The results showed that the treatments that were formulated with ratios of 1 (30 mg/kg) to 3 (90 mg/kg) and 1 (60 mg/kg) to 1 (60 mg/kg) of nanocapsule to sodium nitrite (C and D) have the same efficiency in terms of the ability to inhibit the growth and proliferation of bacterial groups compared to the treatment of 120 mg/kg (A) of sodium nitrite and in the all of storage period, the minimum count of bacteria is related to these treatments. The treatment containing 90 mg/kg of nanocapsules and 30 mg/kg of sodium nitrite (E) had the same ability as treatments A, C and D in inhibiting some bacterial groups until the middle of the storage period. Also, the count level in the treatment containing only nanocapsules (120 mg/kg, B) was significantly lower than the control. The results of measuring the texture characteristics of the treatments showed that the effect of nanocapsules carrying astaxanthin on increasing the water holding capacity of sausages and also reducing of cooking loss, hardness, gumminess, chewiness and tissue cutting is more than sodium nitrite. Springiness, cohesiveness and porosity indices of sausages formulated with different proportions of nanocapsules and sodium nitrite had no significant difference (p>0.05) and were more favorable than the control. In the following, it was found that the texture indicators of the formulated treatments (unlike the control) did not change significantly during the storage period (p>0.05).
 

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The aim of the present research in the first stage was to extract astaxanthin from Haematococcus microalgae (Haematococcus pluvialis) by combined acid-acetone method and evaluate the efficiency of the process. Then, astaxanthin extracted was nanoencapsulated with maltodextrin-sodium caseinate combined coating and physical, antioxidant and color properties of nanocapsules were evaluated along with the pure form of the pigment (during one month of storage at refrigerator temperature). The results showed that with saponification and primary and secondary purification, the efficiency of the extraction process increased and the amount of pigment during the mentioned steps increased from 8.11 to 21.76 mg/g. According to the findings, the size and zeta potential of the produced nanocapsules were 269.1 nm and +46.71 mV, respectively; In addition, the efficiency of the nanoencapsulation process was recorded as 85.19%. The release profile of astaxanthin from nanocapsules in Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF) showed that the release of the pigment varies from 3.21 to 14.28 in SGF and from 18.49 to 41.89% in SIF. Based on the results, the DPPH free radical scavenging activity of pure pigment and nanocapsules (at concentrations of 100 and 200 μg/ml and 0, 15 and 30 days) was ranged from about 21 to 57 and 53 to 70%, respectively. This amount for the reduction power of ferric ion was reported from 0.12 to 0.54 and 0.55 to 0.71 absorbance at 700 nm wavelength, respectively. In the metal chelating activity test, the range of changes was recorded from 23 to 52 and 52 to 75%, respectively. With the nanoencapsulation of the pigment and increasing the concentration, its antioxidant activity increased significantly (p<0.05). Also, unlike the pure form of astaxanthin, the antioxidant activity of its carrier nanocapsules remained constant during storage (p>0.05).
 

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The purpose of present study was to use nanocapsules carrying astaxanthin pigment in common sausage formulation as a substitute for sodium nitrite and search for pathogenic and spoilage microorganisms in the product. For this purpose, after extracting astaxanthin from Haematococcus pluvialis microalgae and producing nanocapsules carrying pigment with maltodextrin-sodium caseinate combined coating, five treatments using different proportions of sodium nitrite and nanocapsules carrying astaxanthin along with control were designed and evaluated in term of the presence of Clostridium perfringens, Staphylococcus aureus, coliform, salmonella, Escherichia coli, Clostridium botulinum, lacticacid bacteria bacteria, yeasts and molds during 28 days of storage at refrigerator temperature. The results showed that in the treatment with the permissible limit of sodium nitrite or 120 mg/kg (treatment A) and also the treatments that this limit was replaced by 30 mg/kg (treatment C) and 60 mg/kg (treatment D) of nanocapsules carrying astaxanthin, the counts of Clostridium perfringens, Staphylococcus aureus, and coliform bacteria were within the standard limit and recorded less than 10 cfu/gr. In treatments containing only 120 mg/kg nanocapsules carrying astaxanthin and also containing 30 mg/kg sodium nitrite and 90 mg/kg nanocapsules carrying astaxanthin (treatment E), only on day 28, the counts of three mentioned bacteria were more than 10 CFU/gr. Further, it was found that none of the research treatments contain Salmonella, Escherichia coli and Clostridium botulinum bacteria. Also, all five formulated treatments were within the standard range in terms of lactic acid bacteria during storage time. The results of counting molds and yeasts showed that this treatments, unlike the control sample, did not have any mold and yeast colonies in the whole of storage period. According to the findings of this research if 50% of permissible sodium nitrite limit using nanocapsules carrying astaxanthin is replaced, it is possible to produce a product free of health-threatening microorganisms.
 

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The purpose of this research was to evaluate the behavior of packaged fish buyers and to identify their priorities for purchasing the product in Tehran city. For this purpose, a questionnaire based on research assumptions was designed and completed by the statistical community. The statistical population of the research is the whole of Tehran city, that 12 urban areas were randomly selected for the field study with a sample size of 600 people. In order to test the hypotheses and examine the intensity of the relationship between the items, a proportional conceptual model was designed and analyzed by Lisrel software. Also, In order to evaluate and rank the priorities of the statistical population in relation to some of product characteristics, Friedman's test was used. The results showed that the variables of packaging characteristics, fish species, processing models, types of supply and quality factors were significantly effective on the attitude, while the quality variable with an effect coefficient of 0.31 had the greatest effect on the attitude. The purchase place also had a significant effect on the perceived behavior control and the hypothesis related to it was confirmed. Among the three main elements of the model, attitude towards consumption with an effect coefficient of 0.63 was the most effective element on the intention to buy. In the following, it was found that two variables, price and access, do not have a significant effect on the purchase decision, and the hypotheses related to them were also rejected. The ranking of purchase priorities of Tehrani citizens in relation to fish species, cultured species, types of supply, pack weights, processing models and shopping places showed that the first rank is related to Persian Gulf fish, rainbow trout, whole fish (empty stomach with head), weight of 500 to 700 grams, schnitzel and protein supply stores.
 

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The purpose of this research was to study the buying and consumption pattern of canned tuna in Mazandaran province using the theory of planned behavior. For this purpose, after determining the research hypotheses, a suitable questionnaire was designed and completed by the statistical community. The statistical population of the research was the entire Mazandaran province that 10 cities were randomly selected for field study with a sample size of 600 people. In order to test the hypotheses and examine the intensity of the relationship between their items, an appropriate conceptual model was designed and analyzed using Lisrel software. According to the findings, about 60% of the households of the statistical population bought and consumed 10 to 12 cans of canned tuna every year. Brand, size 150 to 180 grams, as well as hypermarkets were among the first priorities of the statistical community regarding the three indicators of packaging characteristics, size and shopping places. The results of running the research conceptual model in two modes, standard and significant, showed that only the hypothesis of a significant effect of perceived risk on subjective norms was rejected and other hypotheses were confirmed. According to the results, among the three variables of brand, quality and packaging specifications, canned tuna brand had the greatest effect on buyers' attitudes with an impact factor of 0.52. In the following, it was found that the effect of perceived usefulness on subjective norms (0.56) is more than income (0.43). According to the findings, the price of canned tuna with an effect coefficient of 0.41, advertising and education variable with an effect coefficient of 0.32, and shopping places variable with an effect coefficient of 0.24 were significantly effective on the perceived behavior control element…
 

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The present study was conducted in order to investigate the behavior of shrimp buyers and evaluate their preferences with a statistical population of 600 people in Tehran's Besat market. In this research, shrimp buyers were asked three categories of questions. The questions of the first category were related to demographic characteristics and the questions of the second category were related to the amount and reasons for purchasing shrimp, as well as evaluating the preferences of buyers in indicators such as size, types of supply models, and species of shrimp (Friedman test). The third group of questions were prepared based on the Likert five-option scale and in order to investigate the factors affecting the attitude of the statistical community to the purchase of shrimp by using conceptual model design and structural equation modeling method (Lisrel software). The results of this research showed that buyers who purchase 3 or 4 times a year and selected each time 1 to 1.5 kg of shrimp, had the highest frequency (54.33 and 56.34%, respectively). 64.56 percent of the buyers cited the nutritional value and good taste (together) as the main reason for buying and consuming shrimp. In the study of buyer’s preferences, it was found that large size shrimp (26 to 35 pieces per kilogram), bulk shrimp (compared to packaged and combined shrimp), marine shrimps (compared to cultured and combined shrimp) and the size of 500 to 750 grams of shrimp package have more fans. The results of the implementation of the research conceptual model showed that all hypotheses were confirmed; in such a way that variables of size, types of supply and shrimp species were significantly effective on buyer’s attitudes with effect coefficients of 0.19, 0.33 and 0.47, respectively…