Production of bioactive peptides with antioxidant and antihypertensive activities from wheat gluten using Withania coagulans

This study aimed to produce bioactive hydrolysates and peptide fractions from wheat gluten using Withania coagulans plant protease, and evaluate antioxidant and angiotensin-converting-enzyme inhibitory activities. Plant samples were collected and protease was extracted and purified using precipitation with ammonium sulfate. The enzyme activity was measured (7.3 U/ml) and highest enzyme activity (82%) was observed at 45 °C and pH 5. Wheat gluten hydrolysis was performed for 6 h and the degree of hydrolysis was measured (6.51%). Fractionation of gluten hydrolysates was performed using ultrafiltration and four peptide fractions were obtained, F1 (MW < 3 kDa), F2 (3 < MW < 30 kDa) and F3 (30 < MW < 100 kDa) and F4 (MW > 100 kDa). The highest solubility at pH 4 was exhibited by the F4 fraction. The highest DPPH radical scavenging activity was demonstrated by the F1 fraction. The highest value for angiotensin-converting-enzyme inhibitory activity was obtained for the F2 fraction. Our results showed that wheat gluten hydrolysis with Withania coagulans protease was an effective approach in order to generate bioactive hydrolysates and peptides, which could then be added to functional foods formulations and pharmaceutical products.