The novel autochthonous probiotic strain Lactobacillus brevis BGZLS30-24 improves the functional characteristics of Khorasan wheat sourdough bread

This study focuses on the comprehensive selection and characterisation of 91 autochthonous Lactobacillus strains from traditional dairy products to improve Khorasan wheat sourdough. Among them, 30 strains exhibited high proteolytic activity, particularly against gluten's immunogenic α- and β-gliadin fractions. Phylogenetic and phenotypic clustering revealed specific functional diversity of strains associated with geographical origin. Safety assessments confirmed that selected strains lacked antibiotic resistance and biofilm-forming potential, while exhibiting broad antimicrobial activity. Lactobacillus brevis BGZLS30-24 emerged as the most efficient strain, displaying significant capacity for dough leavening, acidification (pH 3.92±0.03), and extensive degradation of gluten protein fractions, especially in the initial 24 h of fermentation. Metagenomic analysis indicated that inoculated sourdough rapidly developed a dominant Lactobacillus microbiota (92.6% abundance day 1), with improved microbial stability and reduced diversity compared to spontaneous fermentation. The synergistic effect of proteolysis, acidification, and gas production by the BGZLS30-24 strain led to improved dough structure, 12.1% larger loaf volume, and 21.9% softer crumb texture without altering crumb color. Enhanced degradation of gliadins weakened the gluten matrix, suggesting potential for reduced allergenicity. These findings support the use of Lb. brevis BGZLS30-24 as a functional starter culture to produce high-quality, health-oriented Khorasan wheat sourdough bread with improved technological and nutritional properties.