As a promising emerging technology, RF heat sterilization has the advantages of rapid and integral heating,  large penetration depth, high energy efficiency, no chemical contamination, and more uniform in heating the samples. Compared with traditional heat technology, radio frequency heat sterilization can better maintain product quality, so that foods such as red dates will not lose their original taste, nutrition and function. However, during the heating process, the corners of the sample are overheated and the heating performance is unclear, which reduces the efficiency of RF heating. The overall goal of this study was to study the effect of field strength on the heating effect by using a computer simulation model to study the RF heating of red dates while changing the plate spacing. A simulation model of a 10 kW, 27.12 MHz RF system was established using the simulation software COMSOL Multiphysics. Solve the electromagnetic coupling and heat transfer equations in a simulation model in COMSOL Multiphysic. Solve equations using the Heat Transfer Module and transient analysis. In order to maximize the accuracy of the simulation results, a finer mesh is created in the corners of the sample in the processing chamber and in the sample itself when the mesh is built. The magnetic field distribution is obtained by solving the frequency domain equation, and the temperature distribution of the sample is obtained by solving the transient equation. The plate spacing was then changed to observe changes in sample heating rate and uniformity. It can be seen from the simulation results that the temperature in the middle of the sample is higher, and the temperature at the corners of the sample is also higher, and the appropriate reduction of the electrode spacing can improve the rate of RF heating of red dates. The simulation results show that radio frequency can play a good role in heating red dates, but the uneven heating of the samples is affected by the distribution of electromagnetic fields. The model can well simulate important heating effects such as red dates. Combining the simulation results with experiments can improve the heat sterilization efficiency of RF heating.
 

RF heat treatment, Computer simulation, Dielectric properties, Heating uniformity, Red dates