Sourdough yeast-bacteria interactions results in reduced immunogenicity by increasing depolymerization and hydrolysis of gluten

Sourdough is claimed to increase organoleptic and nutritional quality of baked products, to improve digestion and decrease immunogenicity of dough through enzymatic degradation of proteins. The specific role of sourdough strains in protein degradation and immunogenicity reduction has not been clarified, limiting further commercial applications. The current study comparatively investigated the effects of strains (Saccharomyces cerevisiae JM4, Torulaspora delbrueckii JM1 and Pediococcus acidilactici XZ31) selected from sourdough on gluten hydrolysis, depolymerization and immunogenicity during dough fermentation. The results showed that fermentation treatment degraded the polymerization and immunogenicity of gluten mainly by weakening the polymerization ability of glutenin and hydrolyzing glutenin peptides. Gluten in dough fermented with Pediococcus acidilactici XZ31 were more prone to depolymerize than with Saccharomyces cerevisiae JM4 and Torulaspora delbrueckii JM1. The application of Pediococcus acidilactici XZ31 significantly degraded gluten peptides and reduced gluten immunogenicity, however, Saccharomyces cerevisiae JM4 and Torulaspora delbrueckii JM1 had no effect on this. The mixed inocula of Pediococcus acidilactici XZ31 and yeast showed superiority over monoculture in degrading toxic/immunogenic peptides.