Abstract: This study systematically investigated the changes in key physicochemical properties and doneness of Litopenaeus vannamei during thermal processing. The results showed that under 70 ℃ processing conditions, the core temperature of shrimp rose rapidly and stabilized after approximately 5 min; the astaxanthin content first increased and then decreased, corresponding to a color change from brownish to bright red. Protein denaturation and moisture migration induced by thermal processing significantly affected the water-holding capacity, resulting in decreased elasticity and increased hardness of shrimp meat. Scanning electron microscopy (SEM) results confirmed that heat treatment caused structural damage to myofibrils. By matching the key data obtained at 70 ℃ with those at 100 ℃, five critical control points for shrimp during thermal processing at 100 ℃ were identified: 0, 60, 100, 120, and 180 s. On this basis, relevant indicators of shrimp doneness at each control point were further clarified, and a multidimensional doneness evaluation system applicable to shrimp processing was established. This research provides a theoretical basis for the development of processed shrimp products, prepared meal production, and the optimization of intelligent cooking processes.

Key words: cooking doneness; Litopenaeus vannamei; quality changes; food safety