Preparation of Antioxidant Peptides Derived From Quinoa Protein and Evaluation of Their Antioxidant Activity Through a D‐Galactose‐Induced Aging Mice Model

ABSTRACT Quinoa is rich in essential nutrients and bioactive compounds. In this study, six proteases (Neutralase, Papain, Alcalase, Pepsin, Flavourzyme, Trypsin) were used to prepare quinoa protein peptides (QPP), and their antioxidant activity was assessed via in vitro chemical assays and a D‐galactose‐induced aging mouse model. Pepsin‐hydrolyzed QPP showed the highest in vitro antioxidant activity, in which essential amino acids accounted for 55.37% of the total amino acids. In vivo, QPP ameliorated organ index decline and pathological damage in the liver, kidney, and lung of aging mice, increased serum and liver SOD, CAT, GSH‐Px, and T‐AOC activities, reduced MDA levels, and upregulated the mRNA and protein expression of hepatic SOD1, SOD2, CAT, and GSH1 ( p < 0.05). This study identifies pepsin as the optimal protease for preparing QPP and highlights QPP's potential as a natural anti‐aging agent, providing a theoretical basis for quinoa's high‐value application in functional foods.