酸奶加工的全程物理性质变化的研究

Studies on Physical Qualities During different ages of Manufacture and Storage of Yogurt

本文论述了全脂酸奶的加工及贮藏期间pH值、吉尔涅尔度、色度、黏度及比重的物理性质变化。以原料为起点至贮藏保管192h,共11个测定点。结论指出:从原料乳接种发酵到后熟的12h,是乳酸菌产酸的主要阶段,也是粘度、比重显著上升变化的时期,且粘度、比重与酸度的变化呈现高度的显著相关;在原料中添加蔗糖,低温贮藏,有利于防止酸奶的后酸化现象;在酸奶加工和贮藏期间的L(亮度值),a(红色值),b(黄色值)值变化各自的均数差别有高度的显著性;HunterLab色系统分析,即使在低pH值的条件下,适合对酸乳色泽变化进行测定。

The paper introduced changes of pH-value, Thorner, color, viscosity and specific weight, which were important physical qualities during different stages of process and storage of yogurt. From fresh milk to storing 192h, 11 designed points were detected in the research. The conclusion showed that the stage from inoculation to after-ripening 12h was the critical period of lactic acid raising.The viscosity and specific weight also showed evident changes toward increase during the stage. In the conditions of lower temperature 4～6℃and addition of 8%sugar, postacidification of yogurt was inhibited. The changes of color by HunterLab color analyses system