Formulation of apple juice beverages containing whey protein isolate or whey protein hydrolysate based on sensory and physicochemical analysis

Whey protein isolate (WPI) or its bioactive hydrolysate (WPH) was mixed with apple juice along with sweetener, obtaining a series of beverages with various pH values. Sedimentation of WPI-apple juice and WPH-apple juice beverages was inhibited at pH values of 3.15 and 3.47, respectively. The higher the whey protein content, the more undesirable was the taste of samples. A clearer appearance with smaller particle size was obtained with WPH-apple juice formulations compared to WPI-apple juice formulations at pH values closer to the pI of the whey proteins. Intrinsic viscosity measurements revealed the weaker associations of peptides compared with protein molecules.