酪蛋白胶束结构和理化性质的研究进展

Advances in structure and physicochemical properties of casein micelle

酪蛋白是乳中一大类蛋白质的总称,约占乳蛋白质量分数的80%。牛乳中的酪蛋白不是单独存在的,而是和矿质元素相互缠绕在一起而形成的复合物。牛乳的酸凝、酶凝以及液态乳稳定性的变化,从本质上来说都是酪蛋白胶束发生的一系列变化所导致的。本文概述了组成酪蛋白胶束中四种酪蛋白单体各自的结构和理化特征。综述了胶束的组成、胶束的流体力学直径、容积度、密度、水合性、分子间距等几个重要的特征参数。最后总结了核壳模型、双结合模型、亚单元模型和Holt模型等酪蛋白胶束的理论结构模型的特征及各种的缺陷,以期对乳制品的生产和加工提供一些思路。

Abstract.The caseins, a group of unique milk-specific acid-insoluble phosphoproteins, represent approximate eighty percent of the total protein in the milk of cattle. In milk, the caseins are incorporated mainly with colloidal calcium phosphate, rather than monomer molecule. In essence, the coagulation of acidification, rennet and even the stability changes of milk, are all due to the alteration of casein micelles.Therefore, a review was made of the physicochemical properties of casein micelles. Firstly, the structural and physicochemical properties of individual caseins were sketched out.Secondly, some important characteristic parameters of casein micelles were given, including the relative percentage of the caseins and minerals, the hydrodynamic diameters, voluminosity, density, hydration.In the end,various models of the assembly and structure of the casein micelle were critically reviewed. The subunit and Holt models were revealed to be products of muddled thinking and subject to rigid constraints and restrictions,or in the case of the Holt model guilty of serious omission.Both were shown to be particular cases of the dual-binding model when these restrictions were lifted and the omissions made good.This might be helpful for the processing of casein micelle-based products.