Abstract Non-coagulating milk is unwanted in cheese production because it impairs chymosin-induced coagulation properties in bulk milk. Milk samples were analysed to investigate the coagulation process in non-coagulating milk for comparison with milk samples that have a high coagulation ability. This was done by measuring two peptides after chymosin cleavage, namely para-κ-casein and caseinomacropeptide, in all the milk samples using capillary electrophoresis. The results showed that cleavage of κ-casein into para-κ-casein and caseinomacropeptide occurred in both coagulation groups, suggesting that the aggregation stage is the cause of non-coagulating milk. Non-coagulating milk had lower content of para-κ-casein after chymosin addition compared with coagulating milk, which might be the result of a lower content of available κ-casein. Furthermore, this study indicates that there are different mechanisms that explain good coagulation ability and lack of coagulation ability of milk. The results can be useful in understanding the potential chemical mechanisms behind non-coagulating milk.

中文翻译：

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非凝固乳中κ-酪蛋白酶解的研究

摘要 在奶酪生产中不希望使用不凝固的牛奶，因为它会削弱散装牛奶中凝乳酶诱导的凝固特性。分析牛奶样品以研究非凝固牛奶的凝固过程，以便与具有高凝固能力的牛奶样品进行比较。这是通过使用毛细管电泳测量所有牛奶样品中凝乳酶裂解后的两种肽，即副-κ-酪蛋白和酪蛋白巨肽来完成的。结果表明，两个凝固组均发生κ-酪蛋白裂解为副κ-酪蛋白和酪蛋白巨肽，表明聚集阶段是牛奶不凝固的原因。与凝固乳相比，非凝固乳添加凝乳酶后副κ-酪蛋白含量较低，这可能是有效κ-酪蛋白含量较低的结果。此外，本研究表明，牛奶具有良好的凝固能力和凝固能力不足的原因存在不同的机制。结果有助于理解非凝固牛奶背后的潜在化学机制。