Abstract: In order to study the effect mechanism of ultrasonic-assisted thyme impregnation process on the quality of crayfish, the effects of key parameters such as cooking temperature, ultrasonic power and processing time on the water holding capacity, color, textural characteristics, flavor and microbiological safety of the product were systematically investigated. The results showed that with thyme concentration of 1.5%, heating time of 30 min, and heating temperature of 90 ℃, its electronic nose sensor response value was the highest; with cooking temperature of crayfish of 95 ℃ and cooking time of 8 min, the center temperature of the shrimp meat reached 72 ℃, shrimp water retention was better, shrimp shells and shrimp meat had the highest L* value and a* value, while b* value was relatively low, the hardness, cohesion, elasticity, chewing, and viscosity of shrimp were increased significantly, and the total number of colonies was 170 lg(CFU/g); when the ultrasonic power was 80 W and the ultrasonic time was 30 min, the shrimp meat a* value was the highest, the b* value was the lowest, the hardness, resilience and stickiness of crayfish reached the highest value, and the pressurized water loss of crayfish was the lowest, and the total number of colonies was 0 lg(CFU/g). The results of this research could provide process parameter support for the development of new pre-conditioned crayfish.

Key words: crayfish, thyme, ultrasound, process technology