An innovative germination-driven LAB fermentation strategy for allergenicity reduction in soymilk gels through spatiotemporal protease-mediated epitope disruption

Abstract

This study innovatively integrated seed germination (1–3 days) with LAB fermentation to establish a structure-immunomodulation nexus in fermented soymilk gels. Germination degraded hydrophobic proteins, forming soft gels with 84% lower hardness (0.32 N), 57% higher water-holding capacity, and refined porous networks. Structural loosening enabled LAB proteases to access core allergenic domains, cleaving β-barrel (e.g., Gly m 5.03’s E134–S164) and α-helix clusters (e.g., Gly m 5.02’s E118–E124), reducing IgE-binding by 41.4% and antigenicity by 73.3% versus controls. Peptidomics revealed stage-specific degradation: Days 1–2 targeted surface epitopes (e.g., Gly m TI’s I92–K101), while Day 3 cleaved interior IgE-binding regions (e.g., Gly m Bd 30K’s H202–V209). The germination-fermentation cascade synergistically reconfigured protein matrices via hierarchical proteolysis, linking porous gel architecture with immunoreactivity suppression. This dual bioprocessing strategy bridges texture engineering and allergen inactivation, offering a structure-guided approach to develop hypoallergenic plant-based foods.