Physicochemical and untargeted metabolomic analysis of muscle quality and protein degradation in back-split and deveined red shrimp (Solenocera crassicornis) during refrigeration

This study investigated changes in muscle protein degradation in red shrimp ( Solenocera crassicornis ) during refrigerated storage using physicochemical measurements and untargeted metabolomics. Measurements of total volatile basic nitrogen (TVB-N), myofibrillar proteins (MPs) content, Ca 2+ -ATPase activity, total sulfhydryl content, thiobarbituric acid reactive substances values, and muscle microstructure collectively indicated progressive quality deterioration during chilled storage. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of MPs revealed a reduction in the intensity of myosin heavy chain (MHC), α-actinin, actin, and tropomyosin during chilled storage. Muscle protein underwent significant degradation in the middle and later stages of chilled storage. With prolonged chilling, the abundance and variety of small-molecule compounds related to protein degradation increased markedly. Protein digestion and absorption (ko04974) and microbial metabolism in diverse environments (ko01120) were identified as core pathways contributing substantially to muscle protein degradation. Based on these core metabolic pathways, targeted preservation technologies can be developed to inhibit muscle protein degradation. This study provides a theoretical reference for quality control of red shrimp during refrigeration, and lays a foundation for the sustainable development of the red shrimp processing industry.