Recent advances in the mechanism of antioxidant peptides from walnut meal: multi-scale structural characterization...

Walnut meal, the major by-product of walnut oil pressing, is an excellent plant resource with high protein content and well-balanced amino acid composition. Given their potent bioactivity and favorable biosafety, antioxidant peptides enzymatically derived from walnut meal alleviate oxidative stress-associated disorders, making them promising natural substitutes for synthetic antioxidants. Although existing reviews summarize walnut peptide preparation and bioactivities, few integrate multiscale computational chemistry with traditional experiments. This deficiency means there lacks a comprehensive collation of the preparation, purification procedures and structure-activity relationships of walnut antioxidant peptides. This review summarizes and discusses recent advances in research on antioxidant peptides from walnut meal, covering the preparation, separation and purification, identification, as well as computer screening and physicochemical property prediction of such peptides, with Alcalase serving as the dominant enzymatic system for walnut protein hydrolysis. It further addresses the relationship between structural characteristics and antioxidant activities of walnut meal antioxidant peptides, computer-aided simulations analyzing their structure-activity relationship, activity evaluation strategies and action mechanisms centering on core quantitative metrics including molecular docking binding scores, HOMO/LUMO frontier orbital energies, and RMSD-based dynamic stability parameters, alongside existing challenges and future research prospects. The outcomes of this review establishes the theoretical foundation for their exploitation in functional foods and nutritional supplements.