Atmospheric cold plasma alleviates freeze-thaw-induced quality deterioration of hairtail (Trichiurus lepturus) via sacrificial pre-crosslinking of myofibrillar protein.

Hairtail (Trichiurus lepturus) is one of the most consumed marine fish in China, yet its quality is severely compromised by repeated freeze-thaw cycles during cold-chain logistics. This study systematically investigated the protective effects and underlying mechanisms of atmospheric cold plasma (ACP) pretreatment on myofibrillar protein (MP) structure and quality attributes of hairtail subjected to 0, 2, 4, and 6 freeze-thaw cycles. ACP treatment significantly retarded the decline in MP content, solubility, sulfhydryl retention, and Ca2+-ATPase activity, while suppressing carbonyl accumulation and lipid oxidation. Notably, ACP induced a "sacrificial" pre-crosslinking effect-reactive species generated during ACP treatment pre-oxidized a portion of sulfhydryl groups into disulfide bonds prior to freeze-thaw exposure, reinforcing the MP covalent network at minimal oxidative cost. This mechanism effectively preserved hydrogen bond networks and α-helical structures, inhibited the transformation of immobilized water to free water, and maintained microstructural integrity. Remarkably, TVB-N content in ACP-treated samples (29.00 mg/100 g) remained within the national safety limit (≤30 mg/100 g) after 6 freeze-thaw cycles, whereas the control far exceeded it (36.76 mg/100 g). These findings demonstrate that ACP pretreatment offers a promising non-thermal strategy for mitigating freeze-thaw-induced quality deterioration in aquatic products by orchestrating multi-level structural preservation-from molecular conformation to macroscopic texture-providing both theoretical and practical guidance for quality control during cold-chain logistics.