Metabolic dynamics of fermented milk beverages co-fermented with Bifidobacterium animalis subsp. lactis Probio-M8 and Lacticaseibacillus paracasei PC-01 during storage

This work used non-targeted metabolomics technology to monitor the changes in the metabolic profile of fermented milk beverages (FMB) co-fermented by Bifidobacterium animalis subsp. lactis Probio-M8 and Lacticaseibacillus paracasei PC-01 over a 21-day storage period. Specifically, a pairwise comparison was made between the metabolite profile after storage at different time points (1-day storage versus 7-day storage; 7-day storage versus 14-day storage; 14-day storage versus 21-day storage). The comparative analysis revealed a total of 21 discriminatory metabolites, and the enrichment in three key metabolic pathways, namely purine metabolism, ABC transporters, and pyrimidine metabolism during and after storage. The metabolic profile of FMB after 21-day storage was substantially different from those stored only for one day, characterized by having more health-promoting metabolites such as amino acids, vitamins, cytosine, and hypoxanthine. This work has portrayed the changes in FMB metabolic profile over 3-week storage, providing useful reference information on post-fermentation changes of fermented dairy milk products.