Coordinated improvement of shrimp Litopenaeus vannamei preservation quality during super-chilling at -3 °C by combination of chitosan coating with vacuum packing: Efficiency and mechanism.

The quality deterioration of Litopenaeus vannamei during super-chilling exerts a critical challenge for shrimp industry. This study proposes a "antibacterial and oxygen removal-dependent coupling" mechanism to address this challenge. The efficacy of chitosan coating (CC) combined with vacuum packaging (VP) on quality indicators was investigated. Remarkably, the highest sensory score, desirable values of hardness and springiness, the lowest TVB-N contents and activities of protease and polyphenols oxidase (PPO), as well as the significant decrease in TVC and Pseudomonas counts were observed in CC + VP group (P < 0.05). Furthermore, scanning electron microscopy revealed the desirable integrity of myofibrils in CC + VP group than in the samples of CC or VP groups and molecular docking visualized the strong affinity between chitosan with the active sites of PPO, serine protease, calpain and cathepsin B/L in shrimp muscle. Taken together, this study highlights the potential of CC + VP for maintaining shrimp quality during super-chilling.