Effect of cryogenic freezing combined with precooling on freezing rates and the quality of golden pomfret (Trachinotus ovatus)

Abstract Faster food freezing rate can be achieved with a lower cold medium velocity at a lower temperature in the cryogenic freezer. In this paper, the Plank method and the computational fluid dynamics method were adopted to analyze the freezing time and freezing rate of golden pomfrets, respectively. To further increase the freezing rate, samples were precooled in the refrigerator (5°C) or the slurry ice (0°C) before freezing in the cryogenic freezer. The result indicates that the freezing rate of the sample is significantly increased after precooling in the slurry ice. And for the same high freezing rate, the result of the quality testing shows there will be a better frozen quality under a lower cold medium velocity at a lower temperature. In conclusion, precooling in the slurry ice (0°C) and freezing with cold medium of 1.7 m/s at −100°C successively is the most efficient method for maintaining the quality of the frozen golden pomfret. Practical Applications Freezing food with a high freezing rate can realize the shelf‐life extension and long‐term preservation. However, there is little research on how to obtain a better quality of the frozen food at the same freezing rate, namely freezing with a lower cold medium velocity at a lower temperature or with a higher cold medium velocity at a higher temperature. This research demonstrates that the former method is preferable. The result shows that precooling in the slurry ice (0°C) and freezing with cold medium of 1.7 m/s at −100°C successively can significantly increase the freezing rate, which is the most efficient method to improve the frozen quality of the golden pomfret. This process can be well applied in the fast food freezing industry.