Characterization of ACE inhibitory and antioxidant peptides in yak and cow milk hard chhurpi cheese of the Sikkim Himalayan region

•Yak and cow hard chhurpi cheese of Sikkim Himalaya.•ACE-inhibitory activities of undigested and GI digested yak and cow hard chhurpi.•Bioactive peptides identified by LC-MS/MS peptidomics of yak and cow hard chhurpi.•In silico prediction and molecular docking of potential ACE-inhibitory peptides. In this study, simulated in vitro GI digestion of the Himalayan hard chhurpi cheese resulted in the increase of hydrolyzed protein content, antioxidant and ACE-inhibitory activities. LC-MS/MS-based peptidomics revealed a total of 1473 peptides in the samples originating from different milk proteins, including α-S1-casein, α-S2-casein, β-casein, κ-casein, α-lactalbumin, and β-lactoglobulin, out of which 60 peptides have been reported for different functional properties. A total of 101 peptides were predicted to be antihypertensive using the bioactivity prediction web servers, AHTpin and mAHTPred. In silico molecular docking studies predicted 20 antihypertensive peptides, exhibiting non-bond interactions between hard chhurpi peptides and ACE catalytic residues. A peptide, SLVYPFPGPI, identified in GI digested cow hard chhurpi and undigested, and GI digested samples of yak hard chhurpi, showed a stronger binding affinity towards ACE. Identifying antioxidant and ACE inhibitory peptides in hard cheese products adds value to them as functional foods of the Himalayan region.