Germination affects structural and techno-functional properties of proteins from quinoa seeds with increased realease of antioxidant peptides by gastrointestinal digestion

This study investigated the impact of germination on quinoa protein (QP) composition, techno-functional properties, and the release of antioxidant peptides during gastrointestinal digestion. Germinated QP (GQP) at 36 and 48 h showed significant degradation of storage proteins. GQP12 and GQP24 exhibited increased surface hydrophobicity but decreased solubility, foaming, and emulsifying properties, while that of GQP60 and GQP72 were improved. Both QP and GQP demonstrated good digestibility, with over 90 % of their gastrointestinal digests smaller than 1 kDa. Gastrointestinal digests of GQP12 (QPGI12) exhibited excellent antioxidant activity, attributed to higher hydrophobic amino acid content of GQP12 and peptides of QPGI12 digests. Eight antioxidant peptides with strong binding affinity to Keap1 were identified, with peptides FGDL, FGGL, and FDGL interacting through hydrogen bonding and hydrophobic interactions. Findings gained in this study indicated that germination might serve as an efficient strategy for improving techno-functionality and bioactivity of QP for antioxidant peptides production.