The effects of sequential cold extrusion and cysteine (Cys) treatment on the rheological characteristics and in vitro digestibility of whey protein isolate (WPI) were researched in this work. Cold extrusion and Cys treatment increased the apparent viscosity, shear stress, Péclet number, and viscoelasticity of WPI. Furthermore, the emulsifying activity index enhanced in the order of WPI, Cys-treated WPI (Cys-WPI), cold-extruded WPI (CWPI), and extrusion-Cys treated WPI (Cys-CWPI). The emulsion stability index of Cys-CWPI was increased by 29.69% higher than that of WPI. Besides, the α-glucosidase inhibitory rate and xanthine oxidase inhibitory activity in the digests of Cys-CWPI were markedly increased compared with digests of WPI. The synergism of cold extrusion and Cys provides an effective approach for the application of whey protein-based thickeners and emulsifiers; meanwhile, its digestive products may assist in the development of hypoglycemic and uric acid-lowering foods.

中文翻译：

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深入了解顺序挤出和半胱氨酸处理以改善分离乳清蛋白的流变特性和体外消化率


本研究研究了连续冷挤压和半胱氨酸 （Cys） 处理对乳清分离蛋白 （WPI） 流变特性和体外消化率的影响。冷挤压和 Cys 处理提高了 WPI 的表观黏度、剪切应力、Péclet 数和粘弹性。此外，乳化活性指数按WPI、Cys处理的WPI（Cys-WPI）、冷挤压WPI（CWPI）和挤出Cys处理的WPI（Cys-CWPI）的顺序增强。Cys-CWPI 的乳化稳定性指数比 WPI 提高了 29.69%。此外，与 WPI 消化物相比，Cys-CWPI 消化物中 α-葡萄糖苷酶抑制率和黄嘌呤氧化酶抑制活性显著增加。冷挤压和 Cys 的协同作用为基于乳清蛋白的增稠剂和乳化剂的应用提供了一种有效的途径;同时，其消化产品可能有助于开发降血糖和降尿酸的食物。