采用一种较为简单的方法测定牛奶中乳清蛋白变性程度，探讨了不同的预热处理条件和UHT杀菌条件对乳清蛋白变性程度的影响，并测试了市售的全脂奶粉的乳清蛋白变性情况。同时，对比了不同热处理程度的奶粉在经过一定处理后罐装杀菌后的状态。结果表明，牛奶经过低热处理后，乳清蛋白变性程度只有0.15%；经过90℃/30s，110℃/15s，124℃/15s和135℃/15s等模拟鲜奶加工成奶粉过程中不同程度预热处理后，变性程度分别是16%，62%，75%和80%；鲜奶经过中性乳制品常用的不同UHT杀菌条件处理后，乳清蛋白变性程度基本在70%~80%之间。从检测情况来看，市售全脂奶粉一般为高热奶粉。乳清蛋白变性程度对奶粉的应用会有一定程度的影响。%A simple method for testing the denaturation level of whey proteinswas used to investigate the influence of preheat treatment and UHT treatment on the denaturation of whey protein. The denaturation of whey proteins in bovine milk after heat treatment and whey proteins in whole milk powder was measured using this method. The results showed that the whey proteins denatured about 16%,62%,75%,and 80% after heating at 90℃ for 30s,110℃ for 15s,124℃ for 15s,and 130℃for 15s respectively. The denaturation of whey proteins was between 70%and 80% after UHT treatment. In sum,intensive heat treatment has influence on the denaturation of whey proteins. This also indicates that the denaturation level of whey proteins may influence the application of whole milk powder as whole milk powder is normally produced with intensive heat treatment.
展开▼
