不同复合酶水解条件下乳清蛋白功能特性与体外消化行为的比较

Comparison of functional characteristics of whey protein and in vitro digestion behavior under different complex enzyme hydrolysis conditions

摘要:

乳清蛋白是乳制品加工中的重要原料，为改善乳清蛋白的功能特性与消化行为，本研究选取碱性蛋白酶（Alcalase，Ala）与胰蛋白酶（Trysin，Try）进行复配，分别在复合酶（Alc:Try）质量比为（1:1、1:2、2:1）和水解时间（60min、90 min、120 min）的条件下对乳清蛋白进行水解改性。结果表明，经复合酶水解后，乳清蛋白的二级和三级结构发生改变。在复合酶（Alc:Try）质量比为2:1、水解时间120 min的条件下，乳清蛋白的水解度达到28.83%；在该水解条件下乳清蛋白的溶解性提高至99.85%、起泡性提高至58.33%，在该复合酶比例下随着水解时间延长，乳清蛋白的乳化活性指数呈上升趋势，而乳化稳定性指数则在水解60 min时最大，达到99.55%；并且乳清蛋白的热变性温度由78.37℃提升到83.72℃；持水性达到最佳（91.50%）；同时，不同条件下的复合酶水解有效促进了乳清蛋白中的主要过敏原（牛血清白蛋白与免疫球蛋白）在模拟胃肠消化中的彻底分解，具有改善乳清蛋白致敏性的潜力。由此可见，复合酶水解是一种高效的改性策略，为开发高功能的乳清蛋白产品提供了理论依据。

Abstract:

Whey protein is an important raw material in dairy processing. To improve the functional properties and digestive behavior of whey protein, a combination of Alcalase (Ala) and Trypsin (Try) was selected in this study for hydrolytic modification under different composite enzyme mass ratios (Alc:Try at 1:1, 1:2, 2:1) and hydrolysis times (60 min, 90 min, 120 min). The results showed that the secondary and tertiary structures of whey protein were altered after hydrolysis with the composite enzyme. Under the condition of a composite enzyme mass ratio (Alc:Try) of 2:1 and a hydrolysis time of 120 min, the degree of hydrolysis of whey protein reached 28.83%. Under this condition, the solubility of whey protein was increased to 99.85% and foaming capacity was improved to 58.33%. With the same enzyme ratio, the emulsifying activity index showed an upward trend as hydrolysis time increased, while the emulsifying stability index reached its highest value of 99.55% at 60 min of hydrolysis. The thermal denaturation temperature of whey protein was elevated from 78.37°C to 83.72°C, and water-holding capacity reached its optimum level (91.50%). Furthermore, hydrolysis under different composite enzyme conditions effectively promoted the complete degradation of major allergens in whey protein, namely bovine serum albumin and immunoglobulin, during simulated gastrointestinal digestion, indicating potential for reducing the allergenicity of whey protein. Thus, composite enzyme hydrolysis is demonstrated to be an efficient modification strategy, providing a theoretical basis for developing high?functionality whey protein products.