Advanced Food Systems Research Unit, Institute of Sustainable Industries & Liveable Cities and College of Health and Biomedicine, Victoria University, Werribee campus, Victoria 3030, Australia.
School of Science, RMIT University, Bundoora, Victoria 3083, Australia.
Food Res Int. 2018 Dec;114:151-158. doi: 10.1016/j.foodres.2018.08.001. Epub 2018 Aug 3.
Processing of milk results in structural modifications of proteins creating a foundation for various interactions. The present study aimed at identifying the effects of simulated processing conditions, the combination of temperature and shear, on native proteins in raw skim milk. The temperatures chosen (72 and 140 °C) were combined with selected shear rates (0, 500, or 1000 s) during processing. Impact of shear appeared temperature dependent, but it induced either reversible or irreversible changes in the secondary structure of milk proteins at all temperatures. Increase in shear may result in reversible structural modifications at 20 °C, while it could contribute to fragmentation of hydrophobically-linked protein aggregates at 500 s and also reformation at 1000 s during heating at 72 °C. The shearing at 140 °C appeared to enhance the formation of protein aggregates primarily by hydrophobic interactions, as well possibly thiol/disulphide interactions to a lesser extent.
牛奶加工会导致蛋白质结构发生变化，为各种相互作用奠定基础。本研究旨在确定模拟加工条件（温度和剪切的组合）对生脱脂乳中原生蛋白质的影响。选择的温度（72 和 140°C）与加工过程中的选定剪切速率（0、500 或 1000 s）相结合。剪切的影响似乎取决于温度，但在所有温度下，它都会导致乳蛋白二级结构发生可逆或不可逆的变化。在 20°C 时，增加剪切可能会导致结构的可逆变化，而在 500 s 时，剪切可能会导致疏水性连接的蛋白质聚集体的断裂，在 72°C 加热时在 1000 s 时也可能会重新形成。在 140°C 下进行剪切似乎主要通过疏水相互作用增强蛋白质聚集的形成，可能在较小程度上也通过巯基/二硫键相互作用。
