Effects of chlorine dioxide oxidation on the structure and gel functionality of crayfish myofibrillar protein

This study systematically investigated the concentration-dependent effects of chlorine dioxide (ClO₂, 0-150 mg/L) on the structural and gelation properties of crayfish myofibrillar protein. The results demonstrated that ClO₂ decomposition generated hydroxyl radicals (•OH) in a concentration-dependent manner, thereby inducing induced progressive protein oxidation. As the ClO₂ concentration increased, a significant increase was observed in carbonyl content, dimeric tyrosine formation, and surface hydrophobicity, concomitant with a decrease in sulfhydryl groups, free amino groups, and protein solubility. Secondary structure analysis revealed a shift from α-helix to β-sheet and random coil. Moderate oxidation (<100 mg/L) enhanced gel strength through disulfide cross-linking., whereas concentrations exceeding 100 mg/L induced severe oxidation (e.g., methionine oxidation and cysteine trioxidation), resulting in coarse, disordered protein aggregation, significantly compromising gel water-holding capacity. Thus, 100 mg/L is recommended as the optimal threshold to balance disinfection efficacy and protein functionality in crayfish processing.