贮藏期UHT奶中蛋白质组成结构及其糖基化的变化  

Changes in Protein Interactions and Modifications in UHT Milk During Storage

作　　者：李星 顾雨香 任青兮 陈浩然 关凯方 刘海燕 李启明 马莺 LI Xing;GU Yuxiang;REN Qingxi;CHEN Haoran;GUAN Kaifang;LIU Haiyan;LI Qiming;MA Ying(School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150090,China;Xinkong Global Health Co.Ltd.,Chengdu 610044,China;Dairy Nutrition and Function,Key Laboratory of Sichuan Province,Chengdu 610000,China;New Hope Dairy Co.Ltd.,Chengdu 610063,China)

机构地区：[1]哈尔滨工业大学化工与化学学院,哈尔滨150090 [2]新控国际健康管理有限公司,成都610044 [3]乳品营养与功能四川省重点实验室,成都610000 [4]新希望乳业股份有限公司,成都610063

出　　处：《中国乳品工业》2021年第3期10-14,41,共6页China Dairy Industry

基　　金：四川省科技计划项目(2019YFN0119)。

摘　　要：通过测定UHT奶在贮藏过程中蛋白水解,蛋白在胶束相和乳清相的分布,乳蛋白糖基化位点变化,探究乳蛋白在贮藏过程中性质的变化。结果表明贮藏过程中UHT奶中菌落总数增大,纤溶酶含量增大。UHT奶在内外源酶的作用下乳蛋白发生不同程度的水解。热处理导致从胶束表面脱落的κ-CN和乳清蛋白以热诱导聚合物的形式,在贮藏过程中重新结合到胶束表面,从而使胶束粒径增大,牛乳表观黏度增大。贮藏过程中胶束Zeta电位逐渐降低,流动行为指数n逐渐降低,说明牛乳呈现出更明显的剪切变稀能力,暗示胶束结构更加松散。贮藏过程中UHT奶色泽加深,美拉德反应继续进行,其产物半乳糖基赖氨酸和Nε-羧甲基赖氨酸(CML)含量不断增加。Thermal processing of liquid milk is needed to control bacteria levels in dairy products and ensure food safety.Heating induces changes in milk protein structures and consequently alters the way that proteins interact at the molecular and colloidal levels.We investigated protein modifications that occur during long-term storage of raw and ultra-high temperature processed(UHT)milks.Although casein dissociation and whey protein/κ-casein association were found in UHT milk,the level of protein interactions was more pronounced in UHT milk after storage.The amounts ofκ-casein(κ-CN)andβ-lactoglobulin(β-lg)increased gradually in the micelle phase during the storage suggesting that re-association ofβ-lg/κ-CN complexes with the micelles,resulting in an increase in casein micelle size during storage.The early stage Maillard products(lactulosyllysine and CML)were found in UHT-treated milk,with the levels of these products maintained and generally increased with increasing storage time.This work seeks to provide a better understanding of the changes that occur in proteins in UHT milk and its potential implications on milk nutritional quality.

关 键 词：UHT奶 贮藏 蛋白相互作用 糖基化 蛋白水解 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]