Antioxidant and alpha-glucosidase enzyme inhibitory properties of hydrolyzed protein and bioactive peptides of quinoa.

The quinoa protein is gaining global attraction due to high content of gluten-free protein. It is a rich source of high-quality protein with all essential amino acids. The objective of this study was to evaluate the antioxidant activity and alpha-glucosidase inhibition effect of bioactive peptides obtained from quinoa protein hydrolyzed by alcalase and trypsin. Peptides were fractionated using ultrafiltration with MW cut-off = 3, 10 kDa. The peptide concentration was evaluated using OPA solution and peptide bonds were studied by SDS-PAGE. The highest antioxidant activity obtained from quinoa bioactive peptides by alcalase and trypsin was observed after 0.5 h (10 kDa≤) and 4 h (3 kDa≥), respectively. The highest α-glucosidase inhibition activity was observed in peptides with MW 3 kDa ≥ when hydrolyzed by trypsin. The amino acid composition of the most effective samples has been determined. Comparing the results showed that MW and the composition of peptides influenced the studied traits. From the result of this study, it concluded that bioactive peptides obtained from quinoa protein could be used in functional food and supplements formulation.