Co-fermented milk beverage has better stability and contains more health-promoting amino acid metabolites than single-strain-fermented milk beverage over one-month storage

Few studies investigated the effects of co-fermentation with bifidobacteria on post-storage changes of probiotic fermented beverages (PFBs). Thus, this study compared the post-storage changes in physicochemical index and metabolomes of PFBs produced singly by Lacticaseibacillus paracasei PC-01 (PC-01) or in combination with Bifidobacterium adolescentis B8589 (B8589). No significant differences were observed in the pH, titratable acidity, and viable cell counts between the two PFBs over 30-day storage. However, adding B8589 not only increased the stability of PFB (based on evaluating differences in PFBs metabolomics), but also the contents of beneficial amino acid metabolites, including 4-hydroxystyrene, gamma-aminobutyric acid, N-acetyl-l-aspartic acid, d-alanyl-d-alanine, and l-malic acid, after storage. Our study showed that B8589 is preferred to single-strain fermentation by PC-01. This study supports the concept of using bifidobacteria as starter culture in PFB production.