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Some Biochemical properties of silver carp surimi prepared by application of acid-alkali aided methods were investigated and compared to that of derived by conventional method. In terms of total protein solubility and recovery, lipid reduction, and total pigment extractability and myoglobin removal there was a significant (P<0.05) difference among the treatments. Acid-aided method showed the most efficiency to recover more proteins (86.2%) in comparison to the alkaline-aided (79.8%) and conventional (76.7%) methods. The lipid reduction percentage was recorded as 43.6%, 58.4% and 72.3% for the conventional method, and acid-alkali aided methods, respectively. In terms of total pigment removal, the conventional method showed higher efficiency (P<0.05) compared to the pH-shifting methods. Conversely, fish protein solubilisation by acid-alkali aided techniques was more efficient (P<0.05) compared to the conventional method of making surimi. In conclusion, pH-shifting techniques were superior in comparison with the conventional method in order to recover more functional proteins and to efficiently reduce the lipid and myoglobin content of resultant fish protein isolate.

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 The effect of edible chitosan and chitosan-gelatin coating on the quality of fish finger from silver carp during refrigeration was assessed. Fish fingers were immersed separately in coating solutions of chitosan 1% and chitosan 1%-gelatin 4%, packed and stored in refrigerator (4±1˚C) for 30 days, then their chemical (TVB-N, PV, TBA) and microbiological characteristics (TVC and PTC) were analysed. Total volatile basic nitrogen value of coated sample with chitosan was lowest while there was no significant difference between the thiobarbituric acid value of coated treatments (p<0.05). Among the coated samples, chitosan coating effectively reduced  the total viable count (TVC) and psychrotrophic count (PTC). This reduction was 3.2 and 2.6 log₁₀ cfu/g for TVC and PTC at 12 day, respectively, in comparison with control. Thus it can be considered that fish fingers coated with chitosan coating solution was more effective than chitosan-gelatin coating and uncoated samples and increased the shelf life of fish fingers for 18 days.

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The effect of edible whey protein coating and dill (Anethum graveolens) essential oil on the quality and shelf-life of silver carp’s fillets, Hypophthalmichthys molitrix,during refrigeration storage was evaluated. Fillets were immersed in whey protein solution (10%), dill essential oil (5%) and a mixture of whey protein (10%) and dill essential oil (5%), then packed and stored in refrigerator (4˚C). Chemical (PV, TBA and TVB-N) and microbial (TVC and PTC) parameters were measured at 0, 3, 6, 9, 12, 15 and 18 days. The amount of peroxide value and thiobarbitoric acid significantly increased (P < 0.05) in all treatments, but this increace was lower in whey protein coating with dill essential oil fillets. Total volatile basic nitrogen of dill essential oil, whey protein and whey protein with dill essential oil treatments in the first and last phase of storage were 7.55, 7.60, and 7.51- 24.11, 25.84 and 15.55 mgN₂/100 g fillet, respectively. The TVC and PTC amount for whey protein with dill essential oil was lower in comparsion with other treatments. Thus, whey protein coating with dill essential oil increased the shelf-life ofsilver carp’s fillets during refrigerated storage. 

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      Now days, nutritional labeling of fish edible products and calculation of its fillet yield are important needs for fish processing industries. The present study was done to investigate Determination of chemical composition and fillet yield of silver carp (Hypophthalmichthys molitrix) for grading and nutritional labeling of its products by regression equations. For this purpose 50 specimens silver carp were applied in marketing size and their fillet yield, moisture, lipid, protein, ash and energy content were measured. Then, the relationships between these parameters with total length were considered and type of relationship and equation of them were determined. According to obtained results, the relationship between moisture content with fish total length was in inverse linear regression form (p<0.05), while the relationships between lipid, protein and energy content of fillet with fish total length was in positive linear regression form (p<0.05). In generally these equations was in Y= bX± a form. The relationship between protein content and fish total length was significant but weak. According to obtained results there is not relationship between fillet ash content and fish size. Regarding these results and determining their equations, fish length can be used for fish sorting by sorting machine and then economic calculations and determination of moisture, lipid, protein and energy content by obtained equations were done for each group and finally, nutritional labeling and deciding for processing were done for each group.

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Modifications in fat and fatty acid composition of silver carp that take place at each stage of canning process (Precooking and Sterilization) were evaluated. Results showed, precooking led to decrease total fat and increase conjugated dines. The amounts of free fatty acids and thiobarbituric acids had no changed during precooking but these compounds like conjugated dine were increased after sterilization. Steaming had no effect on the fatty acid composition of silver carp however after sterilization as a penetrate of filling media linoleic and linolenic acids to fish tissue, fish fatty acids composition changed. Simultaneous a lot of fish fatty acids penetrate to filling media. This investigation showed, in spite of changes occurred on lipid quality due to canning process, the final product had adequate quality for human consumption.

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  The aim of this study was to evaluate the effect of edible gelatin coating on the quality characteristics and shelf life of fish finger of Hypophthalmichthys molitrix during refrigerated storage. Fish fingers were immersed in coating solutions of gelatin 4% and then dried, packed and stored in refrigerator (4˚C). Chemical (moisture, protein, fat, ash, pH, PV, TBA and TVB-N) and microbial parameters (TVC and PTC) were measured at 0, 3, 6, 9, 12, 15, 18 and 21 days. According to the obtained results by increasing of storage time moisture and fat content decreased and pH value were significantly increased (P < 0.05). While there was no significant difference between the ash content of control and coated samples (P < 0.05). Peroxide value and thiobarbitoric acid of coated samples were lower than the control. The TVB-N value of control and coated samples were 27.80 and 27.46 mg N/100g of flesh fish in 12 days of storage that higher than acceptable value. The total viable count (TVC) and psychrotrophic count (PTC) of fish fingers were significantly increased (P < 0.05) during refrigerated storage. The results of this research indicate that the gelatin coating reduces the oxidation, but has no effect in reducing the value of microbial count.