Changes in Quality Characteristics of Abdomen and Cheliped Muscle of Swimming Crab (Portunus trituberculatus) during Chilled Storage

Objective: To investigate the changes in the quality characteristics of abdomen and cheliped muscle of swimming crab (Portunus trituberculatus) during chilled storage. Methods: The swimming crab was taken as the object. During chilled storage at 4 ℃, the abdomen and cheliped muscle of swimming crab was conducted quantitative descriptive analysis. At the same time, the physicochemical indicators of muscle such as water holding capacity, water content, water activity, pH, total volatile base nitrogen, trimethylamine, TCA-soluble peptide, myofibrillar protein content, and fragmentation index were measured. Results: With the extension of chilled storage time, the characteristics of the abdomen and cheliped muscle of swimming crab showed a similar trend of change, in which the quality sensory characteristics, water holding capacity, water content, and water activity of muscle showed a downward trend. The pH of muscle showed a trend of decreasing first and then increasing. The pH of the abdomen muscle was 7.7 on the 5th day of chilled storage, while the pH of the cheliped muscle reached 7.99 on the 4th day of chilled storage. Total volatile base nitrogen, trimethylamine, TCA-soluble peptide, and myofibril fragmentation index showed an upward trend. The myofibrillar protein content showed a significant downward trend (P<0.05), their content in muscle of abdomen and cheliped reduced by 38.11% and 49.51%, respectively, after 5 d of chilled storage. During the entire refrigeration period, the quality characteristics of abdomen muscle of swimming crab were significantly better than those of the cheliped muscle. Conclusion: With the extension of storage time, the muscle quality of swimming crab gradually deteriorated, and the quality characteristics of abdomen muscle was more stable compared to the cheliped part. This study provides a theoretical reference for quality deterioration and control techniques of swimming crab during chilled storage.