Revealing the protective role of the shell in maintaining muscle quality of crayfish (Procambarus clarkii) during frozen storage

This study focused on the quality changes of cooked crayfish ( Procambarus clarkii ) during frozen storage, analyzing key physicochemical and metabolic alterations under the storage conditions of −20 °C for 120 days. The impact of shell removal on the quality of crayfish meat was also examined by comparing shell-intact and shell-removed samples. The results indicated that with the extension of storage time, the moisture content, water-holding capacity (WHC), and pH of crayfish meat decreased significantly ( P < 0.05) in both the shelled and unshelled groups. The removal of the exoskeleton accelerated the deterioration of the meat, as evidenced by increased TBARS (thiobarbituric acid reactive substances) and TVB-N (total volatile basic nitrogen) levels. The shell-intact group exhibited superior preservation of texture, moisture retention, and overall quality during storage, with better sensory attributes, including hardness, chewiness, and resilience, compared to the shell-removed group. Metabolomic analysis revealed significant shifts in oxidative stability-related metabolites, further supporting the accelerated quality deterioration in the shell-removed samples. Additionally, microstructural analysis showed that the integrity of myofibrillar proteins was better maintained in the shell-intact group, reflecting the protective role of the exoskeleton in mitigating the structural damage caused by ice crystal formation. In conclusion, the presence of the exoskeleton significantly improves the quality preservation of crayfish meat during frozen storage, emphasizing the importance of shell retention for optimizing storage conditions and maintaining product quality. • Prolonged storage negatively affected the physicochemical indexes of crayfish. • Shell can reduce the degradation of proteins and lipids in frozen crayfish. • Changes in metabolites related to oxidative stability were observed in crayfish. • Shell retention can extend the shelf life of cooked crayfish by 23 days.