In vitroantioxidant and angiotensin I-converting enzyme inhibitory properties of enzymatically hydrolyzed quinoa (Chenopodium quinoa) and kiwicha (Amaranthus caudatus) proteins

Background and objectives This study investigated the in vitro antioxidant and angiotensin I-converting enzyme (ACE-I) inhibitory properties of quinoa (QPH) and kiwicha (KPH) protein hydrolysates. Findings Enzymatic treatments with Neutrase for 120 min for quinoa and sequential Alcalase-Neutrase hydrolysis for 240 min for kiwicha protein, both at 50 degrees C, presented high antioxidant activities and ACE-I inhibition (1.50 and 1.67 mu mol TE/mg of protein and 89.2 and 72.8%, respectively) and the lowest IC(50)values (0.08 and 0.29 mg/ml, respectively). After simulated gastrointestinal digestion (pepsin-pancreatin), both protein hydrolysates did not display significant changes in their antioxidant and ACE-I inhibition properties. Conclusions The in vitro antioxidant and antihypertensive properties (ACE-I inhibition) of QPH and KPH obtained via enzymatic hydrolysis using food-grade commercial enzymes were demonstrated. In addition, tested in vitro bioactive properties did not change after simulated gastrointestinal digestion. Significance and novelty The results of this research might be used to obtain QPH and KPH with bioactive properties and/or as starting material for subsequent processes of separation and purification to obtain bioactive peptides.