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

Abstract

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.

Keywords

• Sikkim Himalaya
• Hard chhurpi
• Proteomics
• Bioactive peptides
• Antihypertensive
• Molecular docking