Abstract
The metabolite and peptide profiles of fresh cheese fermented by three novel probiotics, Lacticaseibacillus rhamnosus B6, Limosylactobacillus fermentum B44 and Lacticaseibacillus rhamnosus KF7, were investigated using LC-MS/MS-based metabolomics and peptidomics. The multivariate analysis revealed significant differences in metabolite composition between the probiotic fresh cheese and the control sample. The differential metabolites were primarily lipids and lipid-like molecules and organic oxygen compounds, which were associated with fatty acid and carbohydrate-related pathways. Among three probiotics, L. rhamnosus KF7 showed the highest effectiveness in sucrose decomposition. 147 potential bioactive peptides, mainly derived from casein, were identified in probiotic fresh cheese. Furthermore, 112 bioactive peptides were significantly up-regulated in probiotic fresh cheese. Molecular docking analysis indicated that two short peptides (LVYPFPGPIP and YPQRDMPIQ) in the B44 and KF7 groups exhibited low estimated binding energy values (-9.9 and -6.9 kcal/mol) with ACE. These findings provide a theoretical basis for developing novel probiotic-enriched fresh cheese.