低温冷藏对带鱼肌肉蛋白的影响

Effect of Chilling Storage on the Muscle Protein of Hairtail

中文关键词: 带鱼  冷藏  肌原纤维蛋白  理化指标  降解

英文关键词: Hairtail  Chilling storage  Myofibrillar protein  Physical and chemical indicators  Degradation

中文摘要:

      选取蛋白丰富、营养价值高的舟山大眼带鱼(Trichiurus haumela)，分别置于0℃和4℃冷藏条件下贮藏15 d，通过测定肌原纤维蛋白TCA可溶性肽含量、巯基含量、表面疏水性、Ca2+-ATPase和Mg2+-ATPase活性等一系列可表征带鱼品质变化的理化指标，同时结合全溶性蛋白、水溶性蛋白和高盐溶性蛋白的电泳图，观察低温冷藏对带鱼肌肉蛋白的影响，比较2种贮藏温度下鱼肉蛋白的氧化变性以及降解情况。实验结果显示，在0℃和4℃条件下，随着贮藏时间的延长，TCA可溶性肽含量从1.446 μmol/g分别升至6.717和7.595 μmol/g，巯基含量从38.15 μmol/g MP降至35.82和30.36 μmol/g MP，Ca2+-ATPase活性从0.99 U/mg prot下降至0.092和0.134 U/mg prot，Mg2+-ATPase活性从0.76 U/mg prot下降至0.199和0.125 U/mg prot，表面疏水性先上升后下降，但数值都高于新鲜样。这一系列理化指标数值的改变，反映了0℃和4℃这2种冷藏条件不利于带鱼长期的贮藏，随着贮藏时间的延长，带鱼的蛋白氧化致使其新鲜度和品质都遭到破坏，散发出异味，以至于无法食用。从微观结构来看，带鱼肌肉的全溶性蛋白和水溶性蛋白基本没有变化，但肌原纤维蛋白逐渐降解，也是导致鱼肉品质下降的原因之一。相对于4℃冷藏条件，相同的贮藏天数，0℃冷藏条件下带鱼蛋白降解速率较慢，鱼肉腐败程度较低。

英文摘要:

      The hairtail (Trichiurus haumela) is rich in protein and high in nutrition. In this study, the effects of chilling storage on the muscle protein of hairtail were studied by measuring a series of physical and chemical indicators that characterize changes in the fish quality, including TCA-soluble peptides, sulfhydryl group content, surface hydrophobicity, Ca2+-ATPase activity, and Mg2+-ATPase activity, as well as SDS-PAGE patterns of total soluble proteins, water-soluble proteins, low-salt-soluble proteins, and high-salt-soluble proteins. The effects of 0℃ and 4℃ chilling on the fish muscle protein were observed after 15 days of storage, and the oxidation, denaturation, and degradation of the fish protein under the two storage temperatures were compared. The results showed that after 0℃ and 4℃ storage for 15 days, the TCA-soluble peptides increased from 1.446 μmol/g to 6.717 μmol/g and 7.595 μmol/g, respectively. The Ca2+-ATPase activities were lower than the initial values, decreasing from 0.99 U/mg prot to 0.092 U/mg prot and 0.134 U/mg prot, respectively. The Mg2+-ATPase activities also decreased from 0.76 U/mg prot to 0.199 U/mg prot and 0.125 U/mg prot, respectively. In addition, the sulfhydryl group content decreased from 38.15 μmol/g MP to 35.82 μmol/g MP and 30.36 μmol/g MP, respectively. The surface hydrophobicity first increased and then decreased, but the values were higher than those of the fresh samples. The changes in the values of this series of physical and chemical indicators indicated that the refrigerating conditions of 0℃ and 4℃ were not conducive to the long-term storage of the hairtail. Prolonged storage time destroyed the freshness and quality of the hairtail owing to protein oxidation, which caused a bad odor and rendered the fish inedible. From the microstructure perspective, there were almost no changes in the total soluble proteins and water-soluble proteins. However, the high-salt-soluble proteins degraded under storage, indicating that the myofibrillar protein had degraded gradually, decreasing the fish quality. Moreover, the rate of myofibrillar protein degradation and corruption of the fish was slower at 0℃ than at 4℃ on the same day during storage.