Abstract Coagulation of casein micelles in the stomach is an important factor determining gastric transit and digestion kinetics of proteins. The influence of micellar calcium phosphate (MCP) content on the behaviour of milk proteins during in vitro digestion was studied under simulated infant gastric conditions. Samples (1.5% protein, casein:whey protein ratio = 40:60) were prepared using demineralised whey, milk permeate and skimmed milk, from which the MCP content had been adjusted. For milk samples, turbidity decreased and non-sedimentable casein increased with decreasing MCP content. During in vitro gastric digestion, samples prepared with milk with a higher MCP content showed stronger coagulation and these coagulates were found to digest more slowly. SDS-PAGE analysis showed that casein digestion under these conditions was reduced for samples showing stronger coagulation. The outcomes of this study highlight the importance of casein micelle structure and integrity in determining curd formation during in vitro gastric digestion.

中文翻译：

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胶束磷酸钙对婴儿配方奶粉模型系统中体外胃凝固和乳蛋白消化的影响

摘要 酪蛋白胶束在胃中的凝固是决定胃转运和蛋白质消化动力学的重要因素。在模拟婴儿胃条件下研究了胶束磷酸钙 (MCP) 含量对体外消化过程中乳蛋白行为的影响。样品（1.5% 蛋白质，酪蛋白：乳清蛋白比率 = 40:60）使用脱矿乳清、牛奶渗透物和脱脂牛奶制备，其中 MCP 含量已调整。对于牛奶样品，随着 MCP 含量的降低，浊度降低，不可沉淀酪蛋白增加。在体外胃消化过程中，用较高 MCP 含量的牛奶制备的样品显示出更强的凝固，并且发现这些凝固物消化更慢。SDS-PAGE 分析表明，在这些条件下，酪蛋白的消化对于显示更强凝固的样品来说是减少的。这项研究的结果强调了酪蛋白胶束结构和完整性在体外胃消化过程中确定凝乳形成的重要性。