Lactobacillus casei 1.0351 as an adjunct culture in Cheddar cheese: Modulation of bioactive peptide release and bacterial community dynamics.

This study investigated the effect of adding Lactobacillus casei 1.0351 as an auxiliary strain on the release of antioxidant peptides in Cheddar cheese during a 32-week maturation period. Compared with the control group, the addition of L.casei 1.0351 resulted in higher protein hydrolysis and antioxidant activity in the cheese, with the L.casei group reaching a significant peak at week 28. Furthermore, peptide fractions with a molecular weight of less than 3 kDa exhibited the highest antioxidant activity. Compared with the control group, the L.casei group had a greater number of cleavage sites; the sequenced peptide fragments were mainly derived from αS1-casein and β-casein, and were predominantly short-chain peptides (<20 amino acids). Six antioxidant peptides with 100% homology were identified in cheese supplemented with L.casei 1.0351: αS1-CN f(90-92) (RYL), αS1-CN f(91-94) (YLGY), β-CN f(193-196) (YQEP), β-CN f(169-176) (KVLPVPQK), β-CN f(59-68) (VYPFPGPIPN), and β-CN f(78-91) (TQTPVVVVPPFLQPE). Microbiome analysis revealed that L.casei 1.0351 reshaped the microbial community, increasing the abundance of the Lactococcus, suggesting that microbial community succession plays a key role in shaping the peptide profile. Overall, L. casei 1.0351 promotes the hydrolysis of casein and the formation of bioactive peptides such as antioxidant peptides, providing a theoretical basis for the development of functional cheese products.