Abstract Shearing is an embedded step during thermal processing of milk that can add additional impact on native proteins. Behaviour of native proteins in bovine skim milk was studied at different temperatures (70–100 °C) for 5 min with or without applying a constant shear rate at 1000 s−1. Shear stress generated generally decreased with increase in temperature due to decrease in milk viscosity which displayed a Newtonian fluid behaviour. β-Lactoglobulin (β-Lg) and α-lactalbumin (α-La) denatured rapidly even at low temperature (70 °C) under the shearing and about 25% more of them denatured at 85 °C than those of the non-sheared counterparts. Shearing predominantly induced formation of thiol/disulphide aggregates mainly consisting of β-Lg and α-La, as well other minor whey proteins and caseins. These results highlighted the necessity of assessing impact of shearing on milk proteins when optimising thermal processing conditions.

中文翻译：

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在加热过程中，剪切会加速脱脂牛奶中 β-乳球蛋白和 α-乳清蛋白的变性

摘要 剪切是牛奶热处理过程中的一个嵌入步骤，它可以增加对天然蛋白质的额外影响。在不同温度 (70–100 °C) 下研究了脱脂牛乳中天然蛋白质的行为 5 分钟，在 1000 s-1 下应用或不应用恒定剪切速率。由于牛奶粘度的降低显示出牛顿流体行为，因此产生的剪切应力通常随着温度的升高而降低。β-乳球蛋白 (β-Lg) 和 α-乳清蛋白 (α-La) 即使在低温 (70 °C) 下也能在剪切下迅速变性，其中在 85 °C 下变性的数量比非剪切的多 25%同行。剪切主要诱导硫醇/二硫化物聚集体的形成，主要由 β-Lg 和 α-La 以及其他少量乳清蛋白和酪蛋白组成。