The effect of pH-shifting treatment combined with ultrasound on physicochemical and functional properties of whey protein isolate (WPI) was investigated. After pH 2- or pH 11-shifting (1, 2 and 3 h) and ultrasound treatment (600 W, 30 min), particle size distribution of WPI became narrower and its fluorescence intensity decreased significantly. After WPI was treated with pH 11-shifting for 3 h and ultrasound, it showed the maximum surface hydrophobicity and lowest turbidity (P < 0.05). Meanwhile, pH 2-shifting treatment (3 h) combined with ultrasound could improve emulsion stability of WPI. However, consecutive pH 11-shifting (1–3 h) and ultrasound significantly reduced the emulsifying properties of WPI. Therefore, the combination of pH 2-shifting and ultrasound was a significant method to improve the physicochemical properties of whey proteins.

研究了 pH 转移处理结合超声波对乳清蛋白分离物 (WPI) 理化和功能特性的影响。在 pH 2- 或 pH 11-转变（1、2 和 3 小时）和超声处理（600 W，30 分钟）后，WPI 的粒径分布变窄，其荧光强度显着降低。WPI经pH 11-转变3 h和超声处理后，其表面疏水性最大，浊度最低（P < 0.05)。同时，pH 2-转变处理（3 h）结合超声波可以提高WPI的乳液稳定性。然而，连续的 pH 11 变化（1-3 小时）和超声显着降低了 WPI 的乳化性能。因此，将 pH 2 转换和超声相结合是改善乳清蛋白理化性质的重要方法。