Dual enhancement of pork color stability: Antioxidant activity and myoglobin structural compactness mediated by L-histidine/L-arginine

This study aimed to investigate the effect of L-histidine (His) and L-arginine (Arg) on the color of pork and reveal the possible mechanism. The a* value increased by 2.36 %, 4.78 % and 8.65 % with 0.10–0.30 % His, and by 3.45 %, 8.40 % and 13.06 % with 0.10–0.30 % Arg, respectively (P < 0.05). His/Arg increased oxymyoglobin levels while reducing metmyoglobin levels in dose-dependent patterns. Concomitantly, His/Arg increased sulfhydryl content and decreased reactive oxygen species, TBARS, and carbonyl levels (P < 0.05). Multi-spectral analyses revealed that His/Arg increased the α-helix content and inhibited the unfolding of tertiary structure of myoglobin mainly by interactions with tyrosine residues. Molecular docking simulations suggested that His/Arg could form stable complexes with myoglobin through hydrogen bonding and hydrophobic interactions. These changes might create a protective barrier to limit myoglobin oxidation, thus enhancing color stability. Overall, His/Arg enhanced pork color stability by exerting antioxidant activity and strengthening structural compactness of myoglobin, with Arg demonstrating greater efficacy than His.