Antioxidant activity of bioactive peptides derived from the hydrolysates of jack bean (Canavalia ensiformis (L.) DC.) protein isolate

Jack bean (Canavalia ensiformis (L.) DC.) is commonly cultivated in Indonesia, but not so much available due to the presence of an anti-nutritional substance (hydrogen cyanide, tannin, and canavanine) and its low protein bioavailability. Considering that it is rich in protein, however, we investigated physiological functions of the protein hydrolysates after enzymatic hydrolysis of jack bean protein isolate. The objective of this study was to investigate the antioxidant properties of bioactive peptides from hydrolysis of jack bean protein isolate with pepsin and pancreatin enzyme. The jack bean protein isolate was subjected to digestion by pepsin and pancreatin enzyme separately with time course 15 min, 30 min, 45 min, 60 min, and 120 min. Biological active peptides presenting antioxidant activity was evaluated by determining the activity of free radical DPPH scavenging and its reducing power. The result showed that pancreatin enzyme was able to hydrolyse the jack bean protein more effective than pepsin as indicated by the higher degree of hydrolysis after pancreatin digestion. The highest degree of hydrolysis was achieved at 120 min digestion (28.08 %) with pancreatin. We remarkably found that the jack bean protein hydrolysate after pancreatin digestion presented higher DPPH scavenging activity rather than pepsin. In contrary with DPPH assay, jack bean protein hydrolysates after pepsin digestion exhibited higher reducing power than pancreatin, with the highest reducing power at 30 min digestion. This study suggested that the jack bean protein hydrolysates exhibited potential physiologically functional peptides with antioxidant properties, leading to a beneficial ingredient in the development for nutraceutical agent in promoting of health.