Abstract: In order to explore changes in biochemical properties of muscle proteins from Chinese shrimps (Fenneropenaeus chinensis) during storage at 0 or 4 ℃, basic nutrients, protein composition, salt soluble actomyosin, sulfhydryl content, Ca2+-ATPase activity and hydrophobicity were determined and SDS-PAGE analysis was also conducted at two-day intervals. The results showed that the muscle of Chinese shrimps was a typical food with relatively high protein ((21.75 ± 0.12)%) and low fat ((1.21± 0.03)%). With the extension of storage time, a decrease trend in myofibrillar protein and muscle matrix protein, a pattern of initial increase and final decrease in sarcoplasmic protein and actomyosin, a gradual increase trend in alkali soluble protein and a slow decrease in sulfhydryl content were observed for the muscle of Chinese shrimps. Meanwhile, a significant reduction of Ca2+-ATPase activity was also determined, which exhibited an obvious linear relationship with storage time (R0 ℃= 0.991, R4 ℃ = 0.998). However, the values of the above parameters at 0 ℃ did not significantly differ from those at 4 ℃. Hydrophobicity significantly increased with the extension of storage time, and revealed an obvious linear relationship with storage time (R0 ℃ = 0.976, R4 ℃ = 0.995). SDS-PAGE analysis showed that actin, myosin heavy chain, actomyosin and the protein with a molecule weight of 67 kD were obviously degraded during the storage. Based on a comprehensive consideration of these changes in various indicators, the denaturation of proteins was enhanced due to the extension of storage time. The degree of degradation at 4 ℃ was higher than that at 0 ℃. Ca2+-ATPase activity and hydrophobicity displayed a strong correlation with storage time, which can be considered to indicate the degradation of muscle protein during chilled storage.

Key words: Chinese shrimp (Fenneropenaeus chinensis), muscle, protein, biochemical property