Functional Properties Of Common Carp (Cyprinus Carpio) Myofibrillar Proterins

Surimi myofibrillar proteins are the major proteins in the formation of the gel. Myofibrillar proteins play a major role in the surimi gel, while previous studies focused on surimi washing, adding transglutaminase, and adding a variety of salts to increase surimi gel characteristics. But seldom researches concern myofibrillar proteins attributed to surimi. Therefore, the objective of this study is to improve the myofibrillar proteins functional properties of surimi gel, and the quality characteristics of surimi-based products. This paper features components of common carp fillets, and extraction of myofibril myofibrillar proteins at 8000g for 10min at 4℃three times. Furthermore, he fundamental properties of myofibril proteins, including emulsification, foaming and gelation were examined at different test conditions(i.e. temperature, pH, ionic strength). And myofibrillar proteins gelation was added with inulin to improve its properties so that the inulin can be used in the food industry to improve the quality of surimi. This study provides a theoretical basis, and important practical significance on surimi products.1. The composition of Common Carp: the results indicated that the protein content was 18.7%, moisture 79.8%, and fat 2.1%. The isoelectric point(pI) was determined to be pH5.5, used the lowest protein content in supernatants after precipitation at various pHs as the index. Still, the results of myofibrillar proteins by SDS-polyacrylamide showed that myosin, actin, myoglobin, tropomyosin,α-actin and other elements constituded myofibrillar proteins. Myosin was the major protein, contained the highest of the total.2. Myofibrillar proteins structure and functional properties(1) Myofibrillar proteins solubility assay: solubility of myofibrillar proteins varies at different salts and different concentrations. The results indicated that the solubility of myofibrillar proteins hit the highest at 0.6mol/L NaCl solution, reaching 30%, and the lowest at 0.1mol/L NaCl solution only 4%.(2) Hydrophobicity of myofibrillar proteins: pH of myofibrillar proteins solution ranged from 4 to 8 at 70℃, 80℃and 90℃, resulted that the hydrophobicity of myofibrillar proteins decreased to 53.2%, 17.1% and18.1% of the original level, repectively. In addition, the hydrophobicity of myofibrillar proteins decreased by added with NaCl and Na4P2O7. But myofibrillar proteins hydrophobicity increased significantly from the original 46.3μg to 186.3μg in the heating process, by added with inulin.(3) ATP ase Activity: Adding inulin to carp myofibrillar proteins did not changed Ca2+-ATPase activity significantly, while Ca2+-ATPase activity reached the maximum 0.117μmol/mg at pH 7.(4) Myofibrillar proteins foaming (FC) and foaming stability (FS) aspect: with the inulin concentration increasing, the foaming capacity of myofibrillar proteins went upward. The foaming capacity of myofibrillar proteins reached the highest 85.6% at 2% of protein concentration. Added with 1.25% Inulin, the foaming capacity hit the maximum 88.3%, but reached the lowest 75.6% at pH6.(5) Emulsion activity index and emulsifying stability index: the carp myofibrillar proteins emulsifying activity decreased, to the minimum 1.156m2/g with temperature increased. emulsion stability of myofibrillar proteins lowered to the minimum 4.46% at 50℃, but the emulsifying activity reached the maximum 10.58 m2/g at 0.4mol/L NaCl concentration. On the other hand, added with 0.5% of inulin, myofibrillar protein emulsifying activity reached the maximum of 17.46m2/g, and the myofibrillar protein emulsion stability increased to the maximum 127.18% at 0.75% inulin concentration.3. Myofibrillar proteins functional properties added with inulin: Myofibrillar protein gel characteristics: heating at 80℃under the conditions of inulin adding amount of 1% , myofibrillar proteins gel hardness and elasticity reached the highest; water holding capacity of the gelation increased with the concentration of inulin increasing and declined afterward. On the other hand, whiteness of gelation decreased with the concentration of inulin raising. myofibrillar protein gel hardness and springiness reached the maximum by adding 1% inulin at 80℃. Gel whiteness decreased as the concentration of inulin increased and water-holding capacity decreased and then increased. NaCl, CaCl2 and Na4P2O7 could reduce the hardness and springiness of the myofibrillar protein gel with inulin. Na4P2O7 enhanced water-holding capacity of the myofibrillar gel, while CaCl2 increased gel whiteness. Overall, the amount of added inulin, heating temperature and salt could significantly affect the gel characteristic of Common Carp myofibrillar protein.