pH调节法提取三种贝类分离蛋白及其组成、特性分析

Extraction of three shellfish protein isolates by isoelectric solubilisation/precipitation and their composition and characteristics analysis

在不同p H条件下,采用p H调节法从3种经济贝类(扇贝、文蛤和鲍鱼)肌肉中提取分离蛋白,分析了3种贝类分离蛋白(鲍鱼分离蛋白API、文蛤分离蛋白CPI、扇贝分离蛋白SPI)的组成和基本特性。结果表明,3种贝类分离蛋白碱提最佳p H值均为p H 12,酸沉最佳p H分别为p H 5. 1、5. 1和4. 8。3种贝类分离蛋白的粗蛋白含量均高于80%(干基),溶解曲线均呈现出抛物线形(p H 2. 0～12. 0条件下)。差示扫描量热法(DSC)分析结果表明,SPI、CPI和API的主要吸热峰分别集中在57. 0、63. 6和61. 6℃。SDS-PAGE结果显示,3种贝类分离蛋白中肌球蛋白重链MHC、肌球蛋白轻链MLC和肌动蛋白含量丰富,提取过程中,伴有一些肌原纤维蛋白的降解。根据FAO/WHO/UNU建议,3种贝类分离蛋白必需氨基酸的含量符合成人和婴儿的氨基酸需求,研究结果为贝类分离蛋白作为高品质营养蛋白基料应用于保健食品生产工业中提供理论基础数据。

Proteins were extracted from three economic shellfish(Scallop,Clam and Abalones)by novel isoelectric solubilization/precipitation at different pH conditions.The compositions and characteristics of three shellfish protein isolates were then analyzed.The results showed that the optimal pH for alkali extraction are pH 12 and the optimal pH for acid precipitation of scallops,clam and abalone is 5.1,5.1 and 4.8 respectively.The crude protein content of the three proteins isolates are all above 80%(dry basis).And the solubility of three shellfish protein isolates showed a trend of first decrease then increase from acidic to alkaline pH(2.0-13.0).The results of differential scanning calorimetric(DSC)analysis showed that the major endothermic peaks for Scallop protein isolates(SPI)、Clam protein isolates(CPI)and Abalones protein isolates(API)were centered at approximately 57.0,61.6 and 63.6℃,respectively.SDS-PAGE showed that the three protein isolates are abundant in Myosin HC(MHC),Myosin LC(MLC)and actin with some degradation of myofibrillar proteins during the extraction process.The contents of all essential amino acids in the three protein isolates met FAO/WHO/UNU recommendations for adults and infants.Therefore,the three shellfish protein isolates are a high quality protein for human consumption.The results provide a theoretical basis for the application of shellfish protein isolate as a high quality nutritional protein in health food production industry.