南美白对虾肉糜低温冻藏过程中蛋白质的特性变化

研究南美白对虾肉糜在冻藏过程中的蛋白质特性变化。以虾仁为对照组,主要考察冻藏第0、20、40、60、80、100、120d时在虾仁和虾糜中的pH值、Ca~(2+)-ATPase酶的活性、疏水键、二硫键、水溶性和盐溶性蛋白含量、离子键和巯基类等指标的变化。随着冻藏时间的延长,虾仁和虾糜的pH值,疏水键和二硫键的值都处于升高状态,但是虾糜组的指标都比虾仁低,冻藏120 d的虾糜组分别比虾仁组低0.18、3.28、2.64mg/g;在水溶性和盐溶性蛋白含量、Ca~(2+)-ATPase活性、总巯基、活性巯基、离子键的含量等方面各组数据都处于下降状态,但是虾糜的下降幅度比虾仁小。虾糜组的离子键、水溶性和盐溶性蛋白含量在冻藏120 d后分别比虾仁组高3.62、12.14、5.73 mg/g。在120 d时虾仁的肌原纤维蛋白含量降至新鲜虾仁的38.21%,而虾糜的含量降至43.36%。这表明在冻藏过程中,虾糜的储存形式比虾仁的储存形式更有利于对虾品质的贮藏。本研究的研究结果为虾糜的蛋白等理化品质鉴定提供了理论基础,同时也为虾类产品的精深加工提供了科学依据。

Changes in Protein Characteristics of Minced Shrimp (Litopenaeus vannamei) Meat during Deep-frozen Storage

In this study, the changes of protein characteristics of minced shrimp (Litopenaeus vannamei) meat during frozen storage were investigated. Using shrimp as the control group, the changes in pH, Ca2+-ATPase activity, hydrophobic bond, disulfide bond, water-soluble protein, salt-soluble protein, ionic bonds and sulfhydryl groups of both the minced shrimp meat and shrimp on day 0, 20, 40, 60, 80, 100 and 120 of the frozen storage were examined. With the extension of frozen storage time, the pH, hydrophobic bond and disulfide bond of both the shrimp and minced shrimp meat increased, with those of minced shrimp meat all lower than those of the shrimps (by 0.18, 3.28 mg/g and 2.64 mg/g, respectively on day 120). The contents of water-soluble and salt-soluble proteins, Ca2+-ATPase activity, total sulfhydryl groups, active sulfhydryl groups and ionic bond content of both the shrimp and minced shrimp meat decreased as the frozen storage proceeded, with the decrease for the minced shrimp smaller than that for the shrimps (those of the minced shrimp were higher than those of the shrimps by 3.62 mg/g, 12.14 mg/g and 5.73 mg/g, respectively on day 120). On day 120, the content of myofibrillar protein of the shrimps and minced shrimp meat dropped to 38.21% and 43.36%, respectively, of that of fresh shrimps. Results indicated that storing in the form of minced shrimp is more advantageous than the form of whole shrimps for frozen storage. The results of this study provides a theoretical basis for the evaluation of the protein and other physicochemical indices, and also a scientific basis for the deep processing of shrimp products.