Limited enzymatic hydrolysis reshapes whey protein antigenicity, taste profile, and techno-functional properties

β-Lactoglobulin (β-Lg) is the major allergenic protein in whey, and enzymatic hydrolysis effectively reduces its antigenicity. However, the effects of different proteases on the structure, functionality, flavor, and antigenicity of whey protein isolate (WPI) under comparable degrees of hydrolysis remain insufficiently understood. In this study, WPI was hydrolyzed using alkaline protease, Flavourzyme, trypsin, and chymotrypsin, and its structural characteristics, techno-functional properties, bitterness responses, and residual antigenicity were compared. The results showed that protease type markedly affected the hydrolysis pathway and product composition of WPI, thereby regulating conformational changes, interfacial functionality, and taste profiles. Limited hydrolysis reduced antigenicity while improving emulsifying and foaming properties. Flavourzyme-treated samples showed lower bitterness and bitter-aftertaste responses. Molecular dynamics simulations suggested that β-Lg-IgG binding may involve multiple potential hotspot residues, providing a molecular-level explanation for antigenicity differences among protease-derived hydrolysates. This study provides a theoretical basis for preparing whey protein hydrolysates with reduced antigenicity and bitterness.