Effects of Sous Vide on the Quality Properties of Red Shrimp (Solenocera crassicornis) Muscle during Cooking Process

This study investigated the effects of sous vide (SV) treatments on the quality properties of red shrimp (Solenocera crassicornis) muscle during cooking process. The peeled shrimp and beheaded shrimp were used as the raw materials, which were vacuum-packed and then cooked at 70 ℃ for 5, 8, 10 and 12 min, respectively. The shrimp cooked at 100 ℃ for 2 min in the boiling water were executed as the positive control (CK). The sensory property, color, moisture content, cooking loss, texture, protein content and its extraction yield, total sulfhydryl content, Ca²⁺-ATPase activity of myofibrillar proteins (MPs), and the histological structure of shrimp muscle tissues were determined in this study. The results showed that the L^* and b^* values of SV-cooked shrimp increased continuously, while a^* value increased first and then decreased. The moisture content of shrimp decreased, while the opposite trend was observed for the cooing loss, hardness, and the chewiness of muscle tissues with the prolonged cooking period. The salt-soluble proteins, total sulfhydryl content, Ca²⁺-ATPase activity, and the solubility of MPs decreased continuously during the cooking process. The HE staining and SEM observations indicated that the myofibrils were gradually destroyed due to the heating treatments, resulting in the enlarged space between the muscle fibers and the cracked myofibrils in the muscle tissues. SV cooking treatments increased the sensory scores and moisture content of the shrimp, reduced the cooking loss, hardness, and the chewiness properties when compared with the CK treatment. In addition, the SV cooking also retained the water-soluble and salt-soluble proteins, total sulfhydryl content, and the Ca²⁺-ATPase activity, as well as decreased the insoluble protein content in the shrimp muscle. While, the beheaded shrimp showed more complete structure and the myofibers were arranged more closely than the peeled samples, which thus resulted in the improved texture and flavor of the shrimp products. In conclusion, SV cooking is an advantageous treatment than the traditional boiling method, which effectively retains the flavor quality of shrimp muscle and provides a new idea for the cooked shrimp products.