Optimization of Peptide Preparation from Sacha Inchi Meal and Identification of Antioxidant Peptide Candidates

Abstract Sacha inchi meal, a protein-rich residue from oil extraction, is largely discarded, causing resource waste and low utilization value. Although its protein hydrolysate exhibits antioxidant activity, the underlying mechanism remains unclear. The lack of systematic optimization, peptide identification, and mechanistic investigation restricts the high-value utilization of sacha inchi meal and the development of functional products . This study aimed to optimize the recovery of soluble peptides from sacha inchi meal protein hydrolysate, identify peptide candidates, and explore their potential antioxidant mechanisms through in silico analyses. Alkaline protease hydrolysis was optimized by single-factor and response surface experiments, yielding a hydrolysate with nearly 70% of peptides below 1500 Da. Under the final optimized conditions (59 °C, 4.85 h, solid–liquid ratio of 1:19, enzyme dosage of 8000 U/g), the actual peptide yield reached 62.33% ± 0.71%. The peptides showed strong radical scavenging activity, with DPPH· and ABTS+· scavenging rates reaching 82.27% and 91.08%, respectively. From the <1 kDa fraction, 616 peptides were identified by LC-MS/MS. In silico screening yielded 81 candidate peptides. Among them, WEF and YRPF were computationally prioritized as top-ranked candidate peptides, with the lowest AutoDock Vina docking scores (predicted affinities) against Keap1 (−10.4 and −10.0 kcal/mol, respectively). Their predicted binding poses involved hydrogen bonds and hydrophobic interactions. Molecular dynamics simulations were used for exploratory predictions of the peptide–Keap1 complexes. These findings integrate preparation optimization, peptide identification, and exploratory in silico screening, supporting the valorization of sacha inchi meal as a source of peptide candidates for further functional ingredient research.