FRACTIONATION AND SEPARATION OF PEPTIDES WITH ANTIOXIDANT AND ANGIOTENSIN-I CONVERTING ENZYME INHIBITORY ACTIVITIES FROM A QUINOA (Chenopodium quinoa Willd.) PROTEIN HYDROLYSATE

Abstract

Quinoa proteins were enzymatically hydrolyzed using Neutrase at 50°C/120 min in order to study their antioxidant as well as the angiotensin-I converting enzyme (ACE) inhibitory activities. Subsequently, ultrafiltration (sequentially, 10 and 3 kDa cut-off membranes) and chromatographic techniques (adsorption and size-exclusion chromatography) were applied in order to purify and separate the active fractions. At the end of the separation process, higher values in antioxidant activity (AOA), 3,784.9 μmol TE/g and better ACE inhibitory activities (IC₅₀, 39.1 μg/mL) were obtained which represented 2.3 and 7.7-fold increase compared to the initial hydrolysate, respectively. These findings showed the possible potential of quinoa peptides as a functional ingredient within the food industry.