Whey proteins are becoming an increasingly popular functional food ingredient. There are, however, sensory properties associated with whey protein beverages that may hinder the consumption of quantities sufficient to gain the desired nutritional benefits. One such property is mouth drying. The influence of protein structure on the mouthfeel properties of milk proteins has been previously reported. This paper investigates the effect of thermal denaturation of whey proteins on physicochemical properties (viscosity, particle size, zeta-potential, pH), and relates this to the observed sensory properties measured by qualitative descriptive analysis and sequential profiling. Mouthcoating, drying and chalky attributes built up over repeated consumption, with higher intensities for samples subjected to longer heating times (p < 0.05). Viscosity, pH, and zeta-potential were found to be similar for all samples, however particle size increased with longer heating times. As the pH of all samples was close to neutral, this implies that neither the precipitation of whey proteins at low pH, nor their acidity, as reported in previous literature, can be the drying mechanisms in this case. The increase in mouth drying with increased heating time suggests that protein denaturation is a contributing factor and a possible mucoadhesive mechanism is discussed.

中文翻译：

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乳清蛋白口干受热变性影响

乳清蛋白正成为越来越受欢迎的功能性食品成分。然而，与乳清蛋白饮料相关的感官特性可能会阻碍摄入足以获得所需营养益处的数量。一种这样的特性是口干。蛋白质结构对牛奶蛋白质口感特性的影响先前已有报道。本文研究了乳清蛋白的热变性对理化特性（粘度、粒度、zeta 电位、pH）的影响，并将其与通过定性描述性分析和顺序分析测量的观察到的感官特性相关联。口涂、干燥和白垩属性在重复消耗中累积，对于经受较长加热时间的样品具有更高的强度（p < 0.05）。粘度、pH、发现所有样品的 zeta 电位和 zeta 电位相似，但颗粒尺寸随着加热时间的延长而增加。由于所有样品的 pH 值都接近中性，这意味着乳清蛋白在低 pH 值下的沉淀或其酸度（如先前文献中报道的）都不是这种情况下的干燥机制。随着加热时间的增加，口干的增加表明蛋白质变性是一个促成因素，并讨论了可能的粘膜粘附机制。