Radio Frequency Tempering Multiple Layers Of Frozen Tilapia Fillets: The Temperature Distribution, Energy Consumption, And Quality

Tempering is an important step for the seafood processing industry. Selecting an appropriate tempering method can optimize the quality of tilapia. Volumetric radio frequency heating is able to compete tempering within minutes regardless product sizes. Twelve pieces of frozen tilapia fillets in four layers were used as target samples for a radio frequency tempering study. To improve the tempering uniformity, a thin layer of polyurethane foam was applied in-between layers. The present study explored the optimum radio frequency (RF) tempering processing parameters including three input powers (600, 800, 1000 W) and three electrode gaps (10, 12, 14 cm), batch and continuous mode, and compared it to water-tempering effects on the temperature distribution, drip loss, color, TBARS and texture of tilapia. Results demonstrated that the temperature distribution of tilapia with the optimum RF tempering condition (800 W, 12 cm) was more uniform than water tempering, and the TBARS value of samples tempered by RF is lower than that of water tempering. RF-tempering processes retained the L* value (58.76) and a* value (6.54) of tilapia samples, and also resulted in the highest hardness at 298.59 g. Most of the texture indexes of the tempered tilapia fish show no significant difference (p > 0.05) among all tempering conditions. Thus, RF shows a great potential in fish-tempering industry with its fast, uniform and controllable characteristics and a better retention of fish quality