Effect of Salt Concentration on Muscle Quality of Ready-to-eat Shrimp (Solenocera crassicornis) During Chilled Storage

The effects of NaCl concentrations (0%, 2%, 4% and 6%) on the changes in muscle quality of ready-to-eat shrimp (Solenocera crassicornis) were investigated during 50 days of chilled storage. During 0~50 day of chilled storage, the color, texture, moisture content, water-holding capacity, pH, total volatile base nitrogen (TVB-N) content, total bacterial count, TBA values, and histological changes were determined in the shrimp muscle tissues pre-treated with different NaCl solutions. The results showed that 4% and 6% NaCl treatments significant (P<0.05) inhibited the deterioration changes in the color and texture properties of shrimp muscle and retarded the increased in the TVB-N content, TBA value, and the total bacterial count, when they were compared with the control samples (0% NaCl) during chilled storage. The water-holding capacity of shrimp muscle soaked with NaCl solution increased significantly (P<0.05) during the storage, and the higher concentrations of NaCl treatments maintained the better water-holding capacity of shrimp muscle. As the storage period increased, the water content of shrimp samples increased firstly and then decreased, when the pH values decreased firstly and then increased. While, the shrimp samples soaked with NaCl solutions showed the lower water content and pH than those in the control samples (P<0.05). After 40 days of chilled storage, the higher NaCl concentrations greatly inhibited the deterioration of myofibrils in the shrimp muscle tissues compared with the control samples. The histological structure of the muscle tissues soaked in 4% NaCl solutions was relatively well maintained, and the tighter muscle fibers could be observed in the tissues compared with the control and other NaCl soaked samples. In summary, 4% NaCl soaking treatment could efficiently maintain the muscle quality of ready-to-eat shrimp during chilled storage. The results of this study would provide a theoretical basis and technical support for the development and shelf-life control of ready-to-eat shrimp products.