Development and validation of a susceptor-assisted radio frequency heating strategy for improving uniformity in powdered foods

Abstract

The objective of this study was to model and analyze susceptor-assisted radio frequency (RF) heating for powdered foods, with a focus on improving energy efficiency and heating rate. A 6 kW, 27.12 MHz RF system, combined with a finite element model developed using COMSOL software, was employed to simulate and validate the RF heating process of corn flour in metal susceptors. Experimental results demonstrated that strategically positioning RF wave transmission holes along the long sides of the metal susceptor, particularly near cold spots, resulted in optimal heating uniformity, enhanced heating rate, and improved energy efficiency. Notably, the energy transmission area was identified as the most significant factor affecting overall energy efficiency. The validated simulation showed that the optimal pore diameter increased with the sample's length-width sequence and height. However, when the pore size exceeded a certain threshold, the electric field concentration decreased. Optimized susceptor designs improved energy efficiency by approximately 10 %, with specific configurations achieving 15 % and 18 % enhancements for susceptor sizes of 300 mm × 180 mm and 400 mm × 240 mm, respectively. Additionally, the study established a quantitative relationship between the sample's length-width sequence, height, and optimal pore diameter, with regression errors maintained below 5 %. These findings offer valuable insights into the optimization of RF heating in metallized food packaging, providing a foundation for more energy-efficient designs in industrial applications.