Improvement of radio frequency (RF) heating uniformity for peanuts with a new strategy using computational modeling

•A simulation model was developed and validated to predict RF heating uniformity.•Heating uniformity was improved by adding mica plates and polypropylene blocks at cold spots.•Optimal UI was obtained at thicknesses of 17, 15 and 9 mm for small, medium and large containers.•Lowest UI was obtained at mica plate size (300 × 200 × 15 mm3) for medium containers.

Radio frequency (RF) heating has been considered as an alternative method to traditional thermal treatments for postharvest pasteurization and disinfestations. However, the non-uniform heating in food samples is the main obstacle to be urgently solved. In this study, mica plates were placed on top of the samples with polypropylene blocks placed in between the samples as a new strategy to improve the RF heating uniformity. A computer simulation model was developed based on the commercial software COMSOL to evaluate the temperature distributions. Experiments with peanut samples placed in three dimensions of containers were conducted to validate the simulation model. The results showed that adding mica plates with the similar dimension to the cold spot of samples and increasing the plate thickness effectively improved the RF heating uniformity. Adding polypropylene blocks raised sample average temperatures and finally optimized the RF heating uniformity.