Numerical simulation of temperature distribution during radio frequency tempering of pollack surimi based on dielectric properties

Radio frequency tempering has properties of selective heating. As the increase of temperature, the hotter part of the thawed material absorbs more energy; heat increases rapidly with the change of dielectric properties, while the corresponding cooler part absorbs less energy, which leads to the difference of temperature distribution and will reduce the quality of thawed materials. Increasing uniformity of temperature distribution is most concerned during radio frequency. In this paper, the dielectric properties of pollock (Theragra chalcogramma) surimi were determined by open ended coaxial-line probe method. The regression equations of the dielectric constant and dielectric loss were obtained. Based on the dielectric property, a numerical simulation of the temperature distribution during radio frequency tempering of pollack surimi was carried out by COMSOL Multiphysics software. In order to obtain the physical process of radio frequency tempering for dynamic numerical simulation, the finite element method was used to solve the electromagnetic wave dissipation and heat transfer coupling equation, and was experimentally verified by conducting radio frequency tempering on pollack surimi. The results show that the simulation of coupling equation based on dielcetric property can predict the temperature distribution of the samples accurately during radio frequency tempering.