Preparation of Hypoallergenic Enzymatic Hydrolysates from Crassostrea angulata with In Vitro Immune Tolerance-Inducing Potential

Oyster allergy has emerged as a worldwide food safety concern, and enzymatic hydrolysis is an effective strategy for preparing hypoallergenic oyster products. In this study, crude extract from Crassostrea angulata was hydrolyzed with trypsin, Neutrase, and Flavorzyme. The IgE/IgG-binding activity of the hydrolysates was compared, structures and epitopes were explored, and immune tolerance-inducing potential was evaluated using a T-cell proliferation assay. Under optimized conditions (0.5 h reaction; 1.2% trypsin, 0.8% Neutrase, and 0.4% Flavorzyme), the hydrolysates exhibited markedly reduced immunobinding activity, accompanied by conformational rearrangements and destruction of epitopes. All enzymatic hydrolysates retained certain T-cell epitopes and efficiently stimulated CD4+ T-cell proliferation. Among them, flavorzyme hydrolysate significantly upregulated IL-10 secretion, suggesting its superior in vitro immune tolerance-inducing potential. This study confirms that flavorzyme hydrolysis reduces the allergenicity of oyster, and the hydrolysates possess a strong capacity to induce immune tolerance, supporting the industrial production of hypoallergenic oyster and the development of immune tolerance-inducing agents.