不同加热温度对牦牛乳酪蛋白的影响  

Effect of Heating Temperature on Casein in Yak Milk

作　　者：杨楠[1,2] 梁琪[1,2] 杨敏[2,3] 张卫兵[1,2] 张炎[1,2] 

机构地区：[1]甘肃农业大学食品科学与工程学院,甘肃兰州730070 [2]甘肃省功能乳品工程实验室,甘肃兰州730070 [3]甘肃农业大学理学院,甘肃兰州730070

出　　处：《食品科学》2013年第19期14-18,共5页Food Science

基　　金：国家自然科学基金项目(30960260)

摘　　要：研究随着温度（30～90℃）的上升，牦牛脱脂乳和酪蛋白溶液的热稳定性、乳化性及浊度的变化，并运用扫描电镜观察在此过程中溶液中的酪蛋白胶束表面变化。结果表明：随着温度上升，由于乳清蛋白与酪蛋白的相互作用及酪蛋白自身发生离解、聚集过程，导致脱脂乳和酪蛋白溶液的热稳定性下降、乳化性降低、浊度增大，脱脂乳的增减幅度都明显大于酪蛋白溶液，在70℃以上尤为明显。其中在70～90℃时脱脂乳沉淀量由1.46%增至3.19%，酪蛋白溶液变化较小；乳化活力指数和乳化稳定性两者都随温度上升而降低；脱脂乳浊度在60℃以上显著增加（P＜0.05），酪蛋白溶液由0.28～0.33呈线性增加。The evolution of heat stability, emulsifying properties and turbidity of skimmed yak milk and casein solution was studied during exposure to elevated temperatures （30 to 90 ℃, at each temperature for 15 min）. Meanwhile, scanning electron microscope （SEM） was applied to observe the change on the surface of the casein micelles in the solution during the processes. As a result, due to the interaction of whey proteins with casein, the dissociation and aggregation of casein itself occurring as the temperature was increased, the heat stability and emulsifying properties of skimmed yak milk and casein solution were decreased, and turbidity was increased. Additionally, the variation range of skimmed milk was obviously larger than that of pure casein solution. As the temperature was increased from 70 to 90 ℃, the precipitation capacity of skimmed yak milk was increased from 1.46% to 3.19%, and casein solution presented a smaller change. Both EAI and ES declined with increased temperature. The turbidity of skimmed yak milk significantly increased （P 〈 0.05） at heating temperatures above 60 ℃, and the casein solution showed a linear increase from 0.28 to 0.33.

关 键 词：牦牛脱脂乳 酪蛋白 热稳定性 乳化性 浊度 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]