Abstract:
This study investigated the antioxidant activity and stability of walnut peptide-metal chelates using walnut peptides (WP, Mw<1 kDa) as raw material. The antioxidant capacity of WP chelates with different metal ions prepared by coordination was systematically evaluated, followed by screening of optimal-activity chelates and comprehensive assessment of their antioxidant capacity and stability. Molecular docking was employed to identify the peptide segment exhibiting the strongest antioxidant capacity within walnut peptides and elucidate its specific binding interactions. Results showed that the walnut peptide-calcium chelates (WP-Ca) exhibited significantly enhanced antioxidant activity(
P<0.05), achieving 74.00%±0.54% DPPH and 85.27%±0.67% ABTS
+ radical scavenging rates, surpassing other metal-ion chelates. WP-Ca also maintained high stability across various pH, temperatures, and simulated gastrointestinal digestion. Molecular docking identified NALVAPHY as the optimal peptide for DPPH chelation, with its antioxidant activity mediated by electrostatic interactions and hydrogen bonding with DPPH. This study provides theoretical support for valorizing walnut processing by-products and advances the development of novel metal-chelated peptide antioxidants, with particular implications for functional foods and nutraceuticals.