The effect of Lactococcus lactis CICC 23610 fermentation on the physicochemical properties and flavor formation of oat beverage

Abstract Background and Objectives Probiotic fermentation may contribute to enhancing the flavor and nutrients of grain beverages. The aim of this study was to investigate the effect of Lactococcus lactis ( L. lactis CICC 23610) fermentation on the physicochemical properties, flavor formation, and metabolomics of oat beverages. Findings Results showed that L. lactis CICC 23610 grew rapidly in oat substrate and brought a surge in acidity, apparent viscosity, and β‐glucan content. The final amount of lactic acid, sweet amino acids, and umami amino acids metabolites was also increased. Meanwhile, 15 volatile flavor components (VFCs) were identified as key aroma compounds in fermented oat beverages. The levels of 2,3‐butanedione, propionic acid, hexanoic acid, and heptanone rose, giving the beverage a tart, creamy, and sweet flavor, and the undesirable odors of hexanal, n‐octanal, nonanal, and 2‐pentylfuran were reduced. In addition, significant differences in metabolites based on untargeted metabolomics analyses of oat beverages before and after fermentation were mainly focused on organic acids, fatty acids, and short peptides. The sensory analysis showed that the overall acceptability of fermented oat beverages was significantly improved. Conclusions It could be concluded that the effects of free amino acids (FAAs), organic acids, and VFCs on flavor were mainly reflected in three indicators of odor, acidity, and umami. Significance and Novelty The encouraging results confirmed that probiotic fermentation is a promising method to enhance the overall quality of oat beverages, providing valuable insights into future industrial upgrades of grain beverages.