Non-covalent interactions between whey protein isolate and taxifolin and their potential application in yogurt

This study investigated the interaction mechanism of non-covalent complexes between whey protein isolate (WPI) and taxifolin (Tax) and subsequently applied the complexes into yogurt to evaluate their effects on the quality and functionality of yogurt during storage. The results demonstrated that the WPI and Tax can form granular aggregates with average particle sizes between 184.57 and 287.03 nm. As Tax concentration increases, WPI exhibits enhanced UV–visible absorption alongside intensified static fluorescence quenching, primarily driven by conventional hydrogen bonding and π-alkyl interactions between the two compounds. And the incorporation of the WPI + Tax complex into yogurt significantly improves its water-holding capacity and reduces syneresis, with the WPI + 40 μM group showing the optimal effect. The complexes also enhanced yogurt's antioxidant activity and inhibitory effects against α-glucosidase and α-amylase, which reached the highest levels on day 14 of storage, while maintaining good sensory acceptability. • Whey protein isolate (WPI) and taxifolin (Tax) form a stable non-covalent complex via conventional hydrogen bonds and π-alkly interactions. • The addition of Tax statically quenches the intrinsic fluorescence of WPI and alters its secondary structure. • The addition of the WPI + Tax complex significantly improved yogurt's WHC and reduced syneresis. • The WPI + Tax complex demonstrates significant application potential in the development of functional yogurt.