Impact of Bacillus coagulans Fortification on Storage-Induced Metabolomic Changes in Extruded Mung Bean Snacks

Background: Incorporating probiotic bacteria such as BC, a spore-forming probiotic bacterium known for its resistance, into extruded snacks has emerged as an innovative approach to developing functional foods. Little is known about how the addition influences metabolomic changes during storage. Methods: The mung bean snacks were produced by extrusion, followed by BC fortification. The control snack without seasoning and the two BC treatments (0.1% and 0.5% w/w) were stored at room temperature for 3 months. Culture-based methods and qPCR were performed for microbial analysis. Metabolites were extracted, and metabolite profiles were evaluated using an LC-MS-based approach. Results: 0.5% BC was the most stable in the snack, with viable counts of 7.10 log CFU/g. The PCA plot demonstrated distinct clustering patterns among groups, despite no significant difference by PERMANOVA. In negative mode, L-tyrosine showed higher accumulation in the 0.1 BC group, whereas Threonine, L-histidine, and fatty acid metabolites were highly abundant in the 0.5 BC treatment. The positive mode showed discriminant metabolites, with L-glutamic acid, Isoleucine, and L-phenylalanine enriched in the 0.5 BC treatment. Overall, BC altered citrate and phenylalanine metabolism, and each treatment affected aminoacyl-tRNA biosynthesis. Conclusions: These findings demonstrate the maintenance of culturable B. coagulans in fortified extruded mung bean snacks during storage and provide exploratory insights into metabolite changes associated with amino acid metabolism, lipid oxidation, and flavor development that may be relevant to product quality and storage stability.