Modeling of radio frequency heating of egg white powder continuously moving on a conveyor belt

Abstract

The radio frequency (RF) heating of low moisture foods continuously moving on a conveyor belt is a promising approach for preheating to reduce come-up time and/or pasteurization to ensure food safety. Three-dimensional multiphysics-based models were developed to simulate the RF heating process using two approaches (moving mesh and discrete moving steps) to incorporate the movement of the food product. The models were validated by RF heating of a package of egg white powder (EWP) continuously moving on a conveyor belt for 47 min through the system. The dielectric properties of the porous product were determined by using four mixture equations and their effects on model prediction accuracy were evaluated. The model using dielectric properties calculated by the Complex Refractive Index mixture equation showed best prediction accuracy. The simulated point temperatures from the model using moving mesh approach matched best with the experiment at eight locations inside the food product, with a smallest average Root-Mean-Square-Error value of 3.9 °C. The heating uniformity of the moving EWP was not improved or deteriorated when compared to the stationary product which was heated at the center of the system after 47 min heating.