Angiotensin-I converting enzyme inhibitory and antioxidant activities of protein hydrolysates from Phaseolus lunatus and Phaseolus vulgaris seeds

Abstract

Abstract Phaseolus lunatus and Phaseolus vulgaris protein concentrates were hydrolyzed with the enzymes Alcalase® and Flavourzyme® at different reaction times, and the angiotensin-I converting enzyme (ACE-I) inhibitory activity, antioxidant properties and amino acid composition measured in the hydrolysates. With Alcalase®, the highest degree of hydrolysis (DH) in P. lunatus was 37.94% at 45 min, and in P. vulgaris was 49.48% at 30 min. With Flavourzyme®, the highest DH's were 22.03% and 26.05%, respectively, both at 90 min. ACE-I inhibitory activity in the Alcalase® hydrolysates was IC50 = 0.056 mg mL−1 for P. lunatus at 90 min, and IC50 = 0.061 mg mL−1 for P. vulgaris at 60 min. In the Flavourzyme® hydrolysates this activity was IC50 = 0.0069 mg mL−1 for P. lunatus at 90 min and IC50 = 0.127 mg mL−1 for P. vulgaris at 45 min. In SDS-PAGE, the hydrolysates exhibited low molecular weight bands. Antioxidant activity was 11.55 mmol L−1 TEAC mg−1 protein for P. lunatus with Flavourzyme® at 90 min and 10.09 mmol L−1 TEAC mg−1 protein for P. vulgaris with Alcalase® at 60 min. Amino acid composition exhibited high amino acid hydrophobic residues content.