Determination of Biological Activity of Monascus Cheese and Screening of ACE Inhibitory Peptides

This study aimed to investigate the impact of Monascus on bioactive peptides, particularly angiotensin-converting enzyme (ACE) inhibitory peptides, during cheese maturation. The content of soluble nitrogen, α-glucosidase and ACE inhibitory activities during the ripening process were investigated. Cheese not inoculated with Monascus as a control group. The peptide profile of Monascus cheese was identified. The potential bioactive peptides were screened by bioinformatics and molecular docking, and the selected peptides were synthesized and evaluated. The results showed that compared with the control group, the pH 4.6 soluble nitrogen content (pH 4.6-SN) and trichloroacetic acid soluble nitrogen (TCA-SN) of Monascus cheese were increased by 57.98% and 38.34%, and the α-glucosidase and ACE inhibitory activities were increased by 32.21% and 73.98%, respectively. A total of 1796 peptides were identified in the extract of Monascus cheese, including 51 ACE inhibitory peptides, 28 antioxidant peptides and 7 glucose-lowering peptides. Two ACE inhibitory peptides YPFPGPI and FPEVFGK were selected, whose half-maximal inhibitory concentration values were 207.31 and 410.61 μmol/L, respectively. The inhibition type was non-competitive. This study has provided a rapid screening method for ACE inhibitory peptides, and has proved that the addition of Monascus in cheese can effectively improve the ACE inhibitory activity, which provides a reference for exploring the potential functional properties of Monascus cheese.