Screening of Fermentative Strains for Reducing the Allergenicity of a Whey Protein-Soy Protein System and Genomic Characterization of the Selected Strain.

Dual-protein systems combining whey protein isolate (WPI) and soy protein isolate (SPI) offer complementary nutritional benefits but are limited by the presence of major allergens. Lactic acid bacteria (LAB) fermentation provides a promising strategy to mitigate this limitation. In this study, Lacticaseibacillus paracasei JM053, selected from 13 LAB strains based on phenotypic screening, significantly reduced the in vitro allergenicity of the dual-protein system, increasing the IgE-binding inhibition rate to 48.75%. Whole-genome sequencing and characterization of JM053 revealed a comprehensive proteolytic system, including the proline-specific peptidase genes pepX and pepQ, which may contribute to the degradation of allergenic peptide sequences. Combined with in silico bioinformatic analysis, potential cleavage sites within the linear epitopes of the dual-protein system were predicted based on the substrate specificity of the identified proteases, offering a testable hypothesis for the strain's mechanism of action. In addition, in vitro safety assessment and genomic analysis supported the safety potential, stress tolerance, and probiotic characteristics of JM053. Collectively, this study provides a valuable candidate strain for the development of hypoallergenic dual-protein products and offers preliminary genomic insights into LAB-mediated allergenicity reduction.