Controlled Enzymatic Hydrolysis Modulates IgE-Binding and Functional Behavior of Egg White Proteins

The effects of enzymatic hydrolysis (protease, 3.33-16.67 μkat/g protein) on the allergenicity and techno-functionality of egg white proteins were studied. Proteolysis effectively degraded major allergens (ovalbumin, ovomucoid, lysozyme, and ovotransferrin), significantly reducing IgE-binding capacity. Quantitative FTIR revealed a non-linear, hydrolysis-dependent structural transition dictating egg white functionalities. Moderate hydrolysis (3.33-10.00 μkat/g protein) induced initial protein unfolding, increasing Amide I and II intensities by +39.5% and +55.3%, respectively, which enhanced peptide mobility and accelerated interfacial adsorption, resulting in improved foam stability but a gel network with decreased hardness. Conversely, intensive hydrolysis (16.67 μkat/g protein for 10 h) overcame the disulfide-stabilized structural barrier of ovomucoid, triggering a complete conformational collapse, as confirmed by sharp declines in Amide A (−68.1%), Amide I (−20.8%), and Amide II (−8.8%) intensities. Upon thermal induction, these highly mobile, short-chain peptides underwent structural reassociation, leading to a distinct mechanical “hardness rebound" in heat-induced gels, a recovery in apparent viscosity (n ≈ 1), and maximized deactivation of IgE-binding epitopes. Our results identify tailored hydrolysis windows that balance hypoallergenic requirements with targeted foaming and gelling attributes. Consequently, this work provides a strategic framework for designing high-performance, low-allergen egg white ingredients.