Modulating 11S/7S ratios in lactic acid bacteria‐fermented soy protein gels: effects on physicochemical properties and allergenicity

BACKGROUND: Lactic acid bacteria (LAB) fermentation induces acidic coagulation of soy proteins, primarily composed of β-conglycinin (7S) and glycinin (11S), which exhibit distinct gelation behaviors and allergenic potentials. However, the influence of varying 11S/7S ratios on gel formation kinetics and allergenicity modulation remains unclear. In the present study, we systematically investigated soy protein systems with controlled 11S/7S ratios (FSPI-7S, FSPI-0.5, FSPI-1.0, FSPI-2.0, FSPI-3.0, FSPI-4.0 and FSPI-11S for brevity) under fermentation pH gradients (7.0, 6.5, 6.0, 5.5 and 5.0) to elucidate their synergistic effects on protein aggregation and immunoreactivity. RESULTS: Higher 11S globulin content accelerated protein gelation, with FSPI-11S (100% 11S) gelling at 6 h, FSPI-2.0, FSPI-3.0 and FSPI-4.0 (11S/7S ratio > 1.0) at 8 h, and FSPI-7S, FSPI-0.5 and FSPI-1.0 (11S/7S ≤ 1.0) at 24 h of fermentation. Turbidity and particle size analyses at pH 5.0 confirmed that 11S/7S ratios > 1.0 promoted protein aggregation. Microscopic examination showed that these ratios (≥ 1.0) resulted in denser gel matrices with reduced void formation. Electrophoretic mobility studies revealed that, at pH 6.0, 11S/7S ratios > 3.0 enhanced protein migration and facilitated the incorporation of β-conglycinin subunits into the gel matrix, with preferential migration of basic subunits into the gel network during acid-induced gelation. At pH 6.0, antigenicity assessment revealed superior desensitization occurred when the 11S/7S ratios > 1.0, with FSPI-4.0 exhibiting the lowest antigenicity (6.50%) and FSPI-3.0 exhibiting the lowest immunoglobulin E binding capacity (12.16%). CONCLUSION: The 11S/7S ratio critically governs soy protein gelation properties, where 11S/7S ratios > 1.0 accelerate gel formation, enhance aggregation, and improve matrix density. Superior antigenicity reduction occurs at pH 6.0 with 11S/7S ratios > 1.0. © 2025 Society of Chemical Industry.