关键词: 草鱼, 骨架蛋白, 免疫组化技术, 肌纤维结构, 质构

Abstract: The aim of this work was to investigate the changes of cytoskeletal proteins in the dorsal muscle of grass carp (Ctenopharyngodon idella) during ice storage by immunohistochemistry, and to analyze the changes in the microstructure and textural properties by ultrastructural observation and measurement of shear force and drip loss. In addition, this study clarified the relationship between the degradation of cytoskeleton protein and the deterioration of fish texture, which will a provide theoretical foundation for the quality preservation of freshwater fish. The results showed that cytoskeleton proteins significantly degraded during ice storage. Titin, nebulin, and dystrophin degraded by 76.10%, 78.21%, and 71.14%, respectively. The light and dark bands of grass carp muscle fibers were unclear after 14 days of ice storage. The Z-band and M-band were degraded. and the muscle fiber structure severely broke or became loose. Meanwhile, shear force rapidly decreased from 81 N to 32 N within 10 days of storage, while drop loss increased from 1.6% to 7.8%. Correlation analysis indicated a significantly positive correlation between shear force and the integrated option density (IOD) of titin and dystrophin (P < 0.01). In contrast, a significantly negative correlation was observed between drip loss and the IOD of titin and dystrophin (P < 0.01). The above results showed that the degradation of cytoskeletal proteins may be an important cause of the destruction of muscle fiber and textural deterioration of grass carp during ice storage.

Key words: grass carp, cytoskeleton protein, immunohistochemistry, myofibril structure, texture