Multifunctional bioactive peptides derived from quinoa protein hydrolysates: Inhibition of α-glucosidase, dipeptidyl peptidase-IV and angiotensin I converting enzymes

The study aimed to characterize and identify anti-diabetic and anti-hypertensive bioactive peptides generated upon enzymatic hydrolysis of quinoa protein isolates. Different quinoa protein hydrolysates (QPHs) were produced using food grade enzymes like Bromelain, chymotrypsin and Pronase E at a hydrolysis interval of 2 h up to 6 h. QPHs were characterized for their physicochemical properties using degree of hydrolysis, SDS-PAGE, and their anti-diabetic properties via inhibition of dipeptidyl peptidase-IV (DPP-IV) and α-glucosidase (AG), and anti-hypertensive property via inhibition of angiotensin converting enzyme (ACE) were explored. IC₅₀ for DPP-IV, AG and ACE inhibitory activities of QPHs were in the range of 0.72–1.12, 1.00–1.86 and 0.18–0.31 mg/mL, respectively. The chymotrypsin derived 6 h hydrolysate (QC6) was sequenced for peptides identification and 136 peptides were identified among which 35 peptides were predicted as potential bio-active peptides (BAPs) based on their Peptide Ranker score. Results showed that identified peptides were predicted to possess high potential in inhibiting the DPP-IV, AG and ACE. In particular, QHPHGLGALCAAPPST was found to bind to the highest number of active hotspots of the target enzymes that are involved in their enzymatic activities. In conclusion, quinoa protein hydrolysates were identified as potential sources of BAPs with inhibitory properties towards key enzymes involved in the control of type 2 diabetes and hypertension.