The potential of lactic acid bacteria to reduce the immunogenicity of gliadin

Gliadin is recognized as the primary allergenic protein in wheat, and lactic acid bacteria (LAB) exhibit significant potential for mitigating its immunogenicity. In this study, four strains of LAB were isolated from Chinese traditional sourdough: Lactobacillus fermentum ACX0484, Lactobacillus brevis ACX0303, Lactobacillus curvatons ACX0476, and Lactobacillus plantarum ACX0410. The immunogenicity of gliadin in a gliadin-based medium (GBM) was evaluated using ELISA and SDS-PAGE. Subsequently, Fourier transforms infrared spectroscopy, Intrinsic fluorescence spectroscopy, and Ultraviolet absorption spectroscopy were employed to assess the impact of these LAB on the structural conformation of gliadin. Results demonstrated that all four strains possessed considerable capacity to degrade gliadin after 24 h of treatment, with statistically significant differences observed among the strains (P < 0.05). Notably, the ACX0410 strain exhibited the most pronounced degradation effect, resulting in a 44 % reduction in antigenicity and a 38 % decrease in IgE antibody levels. LAB significantly modified both the secondary and tertiary structures of gliadin. Finally, major allergenic epitopes within gliadin treated by ACX0410 for 24 h were analyzed via HPLC-MS/MS, compared to the control, nine polypeptide sequences were upregulated while seven peptide segments showed down regulation. Importantly, the ω-gliadin sequences APFASIVAGIGGQ and QQPYGSSLTSIGGQ almost completely disappeared after treatment, suggesting that ACX0410 effectively degrades key allergenic epitopes within gliadin.