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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 present study was conducted to evaluate the efficacy of the pH-shift process in protein recovery from whole and gutted common kilka and characteristics of the produced gel compared with muscle surimi obtained with the conventional method. Although both acidic and alkaline methods reduced total pigment (TP) in isolates obtained from the whole and gutted fish, the alkaline version was more effective and the lowest amount of TP was observed in the isolate from gutted fish using alkaline version. The last sample also contained the lowest amount of TCA soluble peptide which was significantly lower than the others. Also, gel produced from the isolate recovered form gutted kilka with the alkaline version had significantly higher water holding capacity and gel hardness but it was weaker than the sample obtained with conventional method. The results were supported with higher relative amount of actomyosin and actin in the structure of the gels produced from the gutted fish isolate and surimi from fish muscle, as reflected in SDS-PAGE. Nevertheless, the whiteness of the samples recovered with pH-shift process was quite lower than the muscle surimi which reveals the necessity of more research in this area.    

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MeHg and total mercury concentrations were determined in the muscle tissues of four fish species (Cyprinus carpio, Rutilus frisii, Carassius auratus and Esox lucius) from Anzali wetland (Guilan, Iran). Fish with the highest amount of MeHg was selected to determine the thermodynamic parameters of MeHg extraction. The extractions process was performed in the range of temperatures 331.15 to 367.15 K and at atmospheric pressure. Results show the extraction of MeHg from SH groups of sulfhydryl proteins was an endothermic process with a positive value for entropy and Gibbs free energy changes at the room temperature. Significant difference was found between MeHg content at T=367.15 K and other temperatures. Correlation coefficients results showed that the mercury concentration in muscle tissue was significantly related to the length and weight of fish (p≤0.01). Also, thermodynamic parameters of methylmercury extractions had significant correlation (p≤0.05) with length and weight of the six fish specimen.

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The aim of this study was to investigate the effect of adding protein concentrate of Bream (Abramis Brama) on chemical properties, texture, color and sensory evaluation of pasta. The fillets were cooked in boiling water for 10 minutes, then minced using a meat grinder. The minced fish was dried at 60 C for 24 hours in an oven and powdered with a grinder. Pasta was prepared with different percentages of FPC (0, 5%, 7.5%, 10%, 15% and 20%). Chemical properties (energy, carbohydrate), tissue tests (hardness, adhesion and resilience), color tests (b, a, L) and sensory evaluation were evaluated. The results showed that by adding fish protein concentrate, the amount of pasta carbohydrate decreased compared to the control sample. In contrast, with increasing fish protein concentrate in pasta, the amount of energy increased significantly (p <0.05). The highest energy content was observed in the pasta containing 20% FPC and the lowest energy content in the control sample. The addition of FPC did not cause any adverse changes in the color of the pasta. The amount of yellow and redness of the pasta increased with the addition of FPC. The amount of pasta patency increased with the addition of fish protein concentrate. The color, taste, chewability, elasticity, odor, filament appearance, adhesion, hardness and overall evaluation of pasta with 7.5% FPC was better than others.  Regarding the texture, color and sensory characteristics of the pasta, it can be concluded that the pasta containing 7.5% fish protein concentrate had better characteristics than other samples.

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  The purpose of this study was production of fish protein isolate and surimi from silver carp (Cyprinus carpio) and investigation of color characteristics as well as some chemical changes of their gel and powder. In this research, proteins were isolated using pH shifts method. Acidic pH (2.5 and 3.5) and basic pH (11 and 12) were used to produce fish protein isolate. Three steps of washing cycles were used for surimi production, which in the third step 0.2 % NaCl was used for more dehydration. Results showed that the product efficiency for fish protein isolate was significantly (P<0.05) more than that for surimi. Furthermore, the produced fish protein isolate using acidic pH had the most production efficiency amongst the samples. As a result, fish protein isolate had more recovery protein content compared to surimi. Determination of fat content of the samples showed that surimi contained significantly (P<0.05) lower reduction in fat compared to fish protein isolate. Investigation and comparison of color characteristics (L, a, b) attributed to gel and powder forms of the samples demonstrated that the produced fish protein isolate using pH 2.5 had the most intensity of lightness (L parameter) amongst the other samples. This study clearly showed that the production efficiency of fish protein isolate was higher than surimi.  In addition due to soluble proteins elimination in the process of surimi production, fish protein isolate had more protein content. The more reduction in fat content of fish protein isolate can be considered as an advantage because of possible increase in durability and safety of the products.  

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  This study aimed to investigate the quality characteristics of fish protein powder (FPP) from common carp raw surimi and its mince prepared by application of freeze-drying technique. To prepare test samples, either distilled water or 0.5M NaCl solution was used and parameters such as water holding capacity (WHC), emulsion capacity (EC), emulsion stability (ES) and oil absorption (OA) were determined. According to the results, WHC did not show any significant differences in samples prepared either by distilled water or 0.5M NaCl solution. In terms of EC, after 6, 12, 24, 48 and 72 h in samples prepared by use of 0.5M NaCl, no significant differences was observed between treatments. However, by use of distilled water, the differences became significantly (P<0.05) different. In this study, FFP from raw surimi showed higher and significant OA capacity compared to the one from fish mince. Finally, among color indices, L* and a* values showed significant difference between FFP from raw surimi and fish mince. It can be concluded that as there was no significant differences between FPP from common carp raw surimi and unwashed mince in terms of functional properties, therefore, if we expect lighter and whiter color in enriched product with protein powder, surimi FPP would be an appropriate choice, however, it needs to be confirmed by sensory evaluation test.  

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The aim of this study was production of fish protein isolate (FPI) and surimi from a low cost and underutilized fish species, carpio (Cyprinus carpio), and investigation of their gel textural properties. FPI was prepared by pH shifting at acidic (2.5 and 3.5) and basic (11 and 12) pHs. Surimi was prepared by 3 times water washing and at the third stage 0.2% NaCl was added to remove the water more efficiently. The results showed that production yield of FPI was significantly (P< 0.05) higher than surimi due to removal of soluble proteins during surimi production. Among the FPI, the FPI produced at acidic condition had higher production efficiency than the others. Protein recovery content of FPI was higher than surimi. FPI prepared at pH 11 showed harder textures compared with the others. Production of hard texture and easy preparation process of FPI compared with surimi were other findings of this study.    

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In the present study, the fish protein isolate (FPI) of wastes of Siberian sturgeon (Acipenser baerii) has been substituted with fish minced (10, 20, 30, and 40%) in preparing fish nuggets. After preparing fish nuggets (88% Silver carp fillet) and initial cooking, the parameters such as approximate analysis, product yield, weight loss, pick-up, microbial growth, and sensory evaluation were investigated. The results showed that the lowest amount of moisture is related to the IP40 Group and no significant difference exists between other treatments. In comparison, the amount of protein in the control sample was the highest (18.00 ± 0.04) and it was decreased with the increase of FPI substitution (P<0.05). The highest amount of weight loss during final cooking was related to the control and IP10 treatments, and the highest product yield was associated with IP20, IP30, and IP40 treatments (P<0.05). The microbial growth results did not show any significant difference among the treatments (P>0.05). Moreover, the sensory evaluation showed the control group, which was only with fish minced, had better taste, smell, texture, etc. than the treatments containing isolated protein. The results of this research showed that the minced fish of silver carp and the FPI by-product can be used to produce fish nuggets, and although in some physical properties, the nuggets containing higher amounts of isolated protein have shown better results, according to the amount of protein and sensory evaluation, the control and the sample containing %10 FPI had better results.

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The aim of this study primary was to evaluate the production possibility of high quality protein powder type A (an almost odorless and tasteless powder with a maximum fat content of 0.75%) from milled meat of common carp through isopropanol solvent extraction method, and then the replacement of produced fish protein powder  (FPP) together with the transglutaminase enzyme instead of flour in the formulation of cake and evaluation of the sensory quality, physicochemical properties and nutritional value at ambient temperature. For experiments, 1 control and 6 experimental cakes treated with 6 and 8% concentrations of fish protein powder by adding 0.5 and 1% transglutaminase levels were considered. The control treatment was free of fish protein and enzyme powders. Factors such as fat, protein, ash and moisture content were significantly different in enriched and control treatments (P<0.05). Peroxide value and pH increased significantly in experimental treatments containing 8% FPP in comparison with other treatments and acidity decreased significantly (P<0.05). Sensory factors including taste, color, texture, odor, and overall acceptability of treatments contain 6% FPP and  0.5% transglutaminase enzyme had no significant difference compared to the control sample (P>0.05). Wih adding transglutaminase enzyme to cakes containing fish protein powder improved the physicochemical properties of the samples.With considering the results and the absence of a significant difference between samples contain 6% FPP and 0.5% enzyme transglutaminase compared to control, this treatment can be recommended as a suitable combination for fish cake.

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