Protein aggregation and Ca2+-induced gelation of soymilk after heat treatment under slightly alkaline conditions
Protein aggregation and Ca2+-induced gelation of soymilk after heat treatment under slightly alkaline conditions
复制标题
微碱性条件下热处理后豆浆的蛋白质聚集和Ca2诱导凝胶
DOI：
10.1016/j.foodhyd.2021.107274
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发表时间：
2021-10-23
影响因子：
10.7
通讯作者：
Guo, Shuntang
中科院分区：
文献类型：
--
作者：
Li, Yue;Wan, Yangling;Guo, Shuntang
豆浆的碱热处理在豆制品生产中得到广泛应用。本研究旨在阐明蛋白质的热聚集状态对豆奶凝固特性的影响。对不同pH值(6.6~8.0)的豆浆进行了预热处理，研究了CaSO4.2H2O诱导的豆浆凝胶化过程及其凝胶特性。结果表明，微碱性处理后蛋白质的聚集和结合模式发生了变化。7S和11S的酸性(A)亚基与11S的碱性(B)亚基结合的能力减弱。这些亚基转化为非颗粒蛋白质，从而降低了颗粒蛋白质含量和颗粒大小。在重组过程中，蛋白质表面的羟基减少了45%-62%，蛋白质亚基中形成了更多的二硫键。在凝胶化过程中，经过碱化处理的豆浆在“预聚集”阶段表现出较慢的分子间结合，导致凝胶化开始时间较晚，凝胶网络较为均匀。随着凝胶中非凝胶蛋白含量的增加，凝胶的持水能力增强，但硬度下降。当pH进一步升高(pH=7.8)到B亚基的等电点时，B亚基过度聚集，形成大而致密的聚集体，从而增加凝胶硬度，形成粗糙不均匀的网络。
Alkaline heat treatment of soymilk is widely used in the production of soy products. This study aimed to clarify the effect of the thermal aggregation state of proteins on the coagulation characteristics of soymilk. Soymilk with different pH levels (6.6-8.0) was preheated, and the gelation processes induced by CaSO4.2H2O and the gel properties were investigated. Results showed that the aggregation and binding pattern of proteins changed after slightly alkaline heat treatment. The ability of 7S and the acidic (A) subunit of 11S to bind to the basic (B) subunit of 11S weakened. These subunits converted into non-particulate proteins, which decreased particulate protein content and particle size. The number of sulfhydryl groups on the protein surface reduced by 45%-62%, and more disulfide bonds formed in the protein subunits during recombination. During gelation, the soymilk after alkaline heat treatment exhibited a slow intermolecular binding in the "pre-aggregation" stage, which led to late gelation onset and a uniform gel network. With the increase in non-gelable protein content in the gel, the water holding capacity (WHC) enhanced and but the hardness decreased. When the pH was further increased (pH >= 7.8) to the isoelectric point of the B subunit, the B subunit excessively aggregated and formed large and dense aggregates, which increased gel hardness and produced a rough and uneven network.