Proteomics analysis of proteolytic system expression of lactic acid bacteria in fermented goat milk with ACE inhibitory potential

The proteolytic system of lactic acid bacteria (LAB) could hydrolyze milk casein into small bioactive fragments with angiotensin converting enzyme (ACE) inhibition activity. However, the proteolytic action of LAB differs during the whole fermentation period. This study aims to depict the differentially expressed proteins (DEPs) of proteolytic system in fermented goat milk (FGM) and explore their relationships with ACE inhibition potential. According to the proteomics analysis, the casein transportation was active in the first phase (0–16 h fermentation) while the peptidase was active in the later phase (16–32 h fermentation). LAB intracellular peptidases (pepM, pepX, pepV, pepO, pepT, and pepP) organized a complex PPI network during the later phase. KEGG analysis indicated that the significant protein enrichments were involved in the ribosome and glycolysis/gluconeogenesis. The understanding of protein profiles of LAB proteolytic system during fermentation provides us a new insight on FGM biological characterization and LABs genetic edition. • The protein expressions of fermented goat milk (FGM) with typical ACE inhibitory activity were compared. • The transportation and peptidases expression of lactic acid bacteria (LAB) varied during fermentation. • LAB intracellular peptidases organized a complex PPI network during fermentation. • The significant enrichment pathways of FGM were involved in ACE inhibition potential.