Gelation mechanism of milk as influenced by temperature and pH; studied by the use of transglutaminase cross-linked casein micelles.
Gelation mechanism of milk as influenced by temperature and pH; studied by the use of transglutaminase cross-linked casein micelles.
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DOI：
10.3168/jds.s0022-0302(03)73741-2
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发表时间：
2003-05
影响因子：
3.5
通讯作者：
A. J. Vasbinder;H. Rollema;A. Bot;C. G. D. Kruif
中科院分区：
文献类型：
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作者：
A. J. Vasbinder;H. Rollema;A. Bot;C. G. D. Kruif
牛奶中的酪蛋白胶束是由四种不同酪蛋白和磷酸钙组成的胶体颗粒，每种都可以与血清相进行交换。酪蛋白和钙在血清相和胶束相之间的分布取决于 pH 值和温度。此外，酸化后，酪蛋白胶束失去胶体稳定性并开始聚集和胶凝。在本文中，我们研究了两种酸诱导胶凝的方法，即 1）在 20 至 50 摄氏度的温度下酸化牛奶；2）在 20 摄氏度时将 pH 值降低至略高于胶凝 pH 值，然后通过升高温度诱导胶凝。这两条路线分别称为 T-pH 和 pH-T。凝胶化动力学和最终获得的凝胶的性质受到所采用的凝胶化途径的影响。 pH-T 奶在较高 pH 值和较低温度下凝胶，形成的凝胶更坚固，并且对脱水收缩的敏感性更小。通过使用胶束内交联的酪蛋白胶束，其中血清酪蛋白的释放被阻止，我们证明未加热的牛奶血清酪蛋白在凝胶动力学和最终形成的凝胶的特性中发挥着关键作用。该机制以模型形式呈现，与优化和控制乳制品行业的工业流程相关，例如酸化乳制品的巴氏灭菌。
Casein micelles in milk are colloidal particles consisting of four different caseins and calcium phosphate, each of which can be exchanged with the serum phase. The distribution of caseins and calcium between the serum and micellar phase is pH and temperature dependent. Furthermore, upon acidification casein micelles lose their colloidal stability and start to aggregate and gel. In this paper, we studied two methods of acid-induced gelation, i.e., 1) acidification of milk at temperatures of 20 to 50 degrees C and 2) decreasing the pH at 20 degrees C to just above the gelation pH and subsequently inducing gelation by increasing the temperature. These two routes are called T-pH and pH-T, respectively. The gelation kinetics and the properties of the final gels obtained are affected by the gelation route applied. The pH-T milks gel at higher pH and lower temperature and the gels formed are stronger and show less susceptibility to syneresis. By using intramicellar cross-linked casein micelles, in which release of serum caseins is prevented, we demonstrated that unheated milk serum caseins play a key role in gelation kinetics and characteristics of the final gels formed. This mechanism is presented in a model and is relevant for optimizing and controlling industrial processes in the dairy industry, such as pasteurization of acidified milk products.