Bioactive peptides derived from quinoa protein: fabrication, antioxidant activities, and in vitro digestion profiles

Quinoa protein is increasingly being used a source of plant protein in the food industry because of its high nutrient value, good digestibility, and gluten-free nature. However, its widespread application in the food industry is currently restricted due to its poor water solubility and limited functionality. Controlled enzymatic hydrolysis can improve the functional attributes of plant proteins. Consequently, the objective of this study was to produce bioactive peptides from quinoa protein by enzymatic hydrolysis. The suitability of five commercial proteases were assessed for this purpose: alcalase, compound protease, neutral protease, flavourzyme, and papain. The antioxidant activity and digestion properties of the peptides produced were analyzed. Alcalase was the most efficient enzyme for treating quinoa protein, as it produced the highest degree of hydrolysis, nitrogen recovery rate, and antioxidant activity. Amino acid analysis indicated that quinoa peptides contained all the essential amino acids required for human nutrition, as well as a high level of hydrophobic amino acids, which may provide strong antioxidant activity. In vitro digestion analysis showed that the quinoa peptides exhibited strong resistance to hydrolysis in the stomach but were hydrolyzed in the small intestine. After simulated gastrointestinal digestion, the peptides still exhibited high antioxidant activity. This study therefore suggests that bioactive peptides derived from quinoa protein could be utilized as bioactive ingredients to formulate functional foods.