4℃诱导解离对山羊乳酪蛋白胶束结构的影响  

Effect of dissociation induced by 4℃on caprine casein micelle structures

作　　者：张杰龙 潘丽娜 彭小雨 李威 刘大松[1] 周鹏[1] ZHANG Jielong;PAN Lina;PENG Xiaoyu;LI Wei;LIU Dasong;ZHOU Peng(State Key Laboratory of Food Science and Technology,Jiangnan University,Wuxi 214122,China;Ausnutria Dairy(China)Co.Ltd.,Changsha 410200,China)

机构地区：[1]江南大学食品科学与技术国家重点实验室,江苏无锡214122 [2]澳优乳业(中国)有限公司,湖南长沙410200

出　　处：《食品与发酵工业》2024年第7期131-139,共9页Food and Fermentation Industries

基　　金：国家自然科学基金青年科学基金项目(31901613);江南大学食品科学与技术国家重点实验室自由创新探索资助课题(SKLF-ZZA-202004);江南大学基本科研计划青年基金项目(JUSRP121077);湖南省科协科技人才托举工程(2022TJ-XH-047)。

摘　　要：山羊脱脂乳于25℃超离心,分为乳清和胶束,后者复溶于脱脂乳超滤液,于4℃超离心,分为乳清和胶束,探究4℃诱导解离对胶束结构的影响。4℃下超离心和超滤液复溶2次后,胶束态酪蛋白的解离达平衡,总酪蛋白的解离达36.5%,其中β-、κ-、αs-酪蛋白的解离达60.4%、31.4%、11.8%;25℃下游离β-酪蛋白以2P、3P和4P的低磷酸化形式存在,4℃下胶束钙的解离导致5P和6P的高磷酸化β-酪蛋白的解离;4℃诱导解离后,胶束钙相对含量从72.0%减少至50.2%,胶束中钙与酪蛋白物质的量之比从21.8减少至19.4,胶束仍保持完整的球状形貌,胶束均方回转半径R_(g)、流体力学半径R h、重均分子质量均减小,胶束形状因子R_(g)/R h、水合率和内源荧光强度均增加,胶束内部结构中酪蛋白空间分布的非均一性降低,表明低温诱导解离后胶束内部组分发生了重排,骨架结构变得更加松散。该研究为羊乳酪蛋白配料的分离提供参考。Caprine skim milk was ultracentrifuged at 25℃and divided into whey and micelles.The latter was dissolved in the caprine skim milk ultrafiltration fluid,was ultracentrifuged at 4℃,and divided into whey and micelles.The effects of dissociation induced by 4℃on caprine casein micelle structures were investigated.The dissociation of micellar casein reached equilibrium after ultracentrifugation at 4℃and reconstitution in ultrafiltration fluid two times.The dissociation rate of total casein was 36.5%and the dissociation rate ofβ-,κ-,andαs-casein were 60.4%,31.4%,and 11.8%separately.Solubleβ-casein at 25℃existed in the form of low phosphorylation containing 2P,3P,and 4P.The dissociation of colloidal calcium at 4℃led to the dissociation of high-phosphorylatedβ-casein containing 5P and 6P.After dissociation induced by 4℃,the relative calcium content of caprine micelle decreased from 72.0%to 50.2%.The molar ratio of calcium to casein decreased from 21.8 to 19.4.Casein micelles remained in complete spherical morphology.The mean square radius of gyration(R_(g)),hydrodynamic radius(R h),and weight average molecular weight of micelles all decreased.Micelle shape factor R_(g)/R h,hydration rate,and endogenous fluorescence intensity all increased.The local protein inhomogeneity within the micelles reduced,suggesting that the internal components reorganized and the frame structure became looser.This study provides a reference for the separation of caprine casein ingredients.

关 键 词：山羊脱脂乳 酪蛋白胶束 低温诱导解离 酪蛋白磷酸化 胶束钙 胶束半径 胶束分子质量 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]