Preparation and identification of dipeptidyl peptidase IV inhibitory peptides from quinoa protein

The objective of this study was to investigate the dipeptidyl peptidase IV (DPP-IV) inhibitory properties of quinoa protein-derived peptides. After germination, quinoa protein was extracted and then hydrolyzed by different enzymes such as papain, Alcalase, Neutrase, and Flavourzyme and pepsin-trypsin digestion. Results showed that the quinoa protein hydrolysates (QPH) by pepsin-trypsin digestion displayed the highest DPP-IV inhibitory activity. When ultrafiltrated, the fraction of quinoa protein hydrolysate with molecular weight less than 1 kDa (QPH1) exhibited a superior DPP-IV inhibitory activity with IC