Reducing the allergenicity of αs1-casein by Lactiplantibacillus plantarum JY067 fermentation

αs1-casein is one of the core allergens in milk allergy, posing a significant risk for infants due to its high content and absence in breast milk. Consequently, reducing the allergenicity of αs1-casein has become a critical issue in the dairy industry. This study identified a strain, Lactiplantibacillus plantarum (L. plantarum) JY067, capable of significantly reducing the allergenicity of αs1-casein (the antigen suppression rate was 72.27 %). The mechanisms underlying this reduction were analyzed from molecular structure, physicochemical properties, and peptidomics profiling. Structural analysis revealed that with increasing fermentation time, the higher-order and microscopic structures of αs1-casein gradually unfolded, transitioning from ordered to disordered states. Physicochemical properties showed significant increases in the degree of hydrolysis and DPPH radical scavenging rate (2.29 and 1.52 times higher than control group (unfermented αs1-casein at 0 h)), along with a notable increase in the type and content of free amino acids. Surface hydrophobicity and free thiol groups decreased by 21.27 % and 23.69 %, respectively. Allergenicity results indicated a significant reduction in IgE and IgG binding capacities. Peptidomics profiling identified 50 peptide fragments belong to αs1-casein, with 12 potential allergenic epitopes identified, and only 3 allergenic peptides detected after 27 h of fermentation. Thus, fermentation with L. plantarum JY067 is an effective strategy for reducing the allergenicity of αs1-casein. This study provides important data and practical applications for lowering milk allergenicity.