Molecular mechanisms underlying the beneficial effects of fermented yoghurt prepared by nano-exopolysaccharide-producing Lactiplantibacillus plantarum LCC-605 based on untargeted metabolomic analysis

Following our previous discovery that Lactiplantibacillus plantarum LCC-605 secreted spherical exopolysaccharide nanoparticles (EPS-605 NPs), which may contribute to the quality, function, and stability of the fermented yoghurt. We thus prepared the fermented skim milk with strain LCC-605 (Y-605) and investigated the functions and metabolic changes of Y-605. Y-605 showed excellent antioxidant activities with DPPH, ABTS +, and hydroxyl scavenging ability of 90.6 ± 0.1 %, 96.1 ± 0.2 %, and 99.3 ± 0.4 %, respectively, and cholesterol-lowering ability up to 39.9 %. After storage for 7 days, the bacterial count reached 10.9 log CFU/mL. EPS production significantly improved the water holding capacity (71.7 ± 0.5 %), and the texture of the yoghurt. Untargeted metabolomic analysis further revealed significant metabolomic differences between skim milk and Y-605, validating the beneficial mechanism of Y-605. This study develops a novel probiotic for producing functional yoghurts and provides the basis for understanding the beneficial mechanism of Y-605.