Recent developments in radio frequency drying of food and agricultural products: A review

Radio frequency (RF) drying is an effective and practical dielectric drying method for food and agricultural products due to rapid and volumetric heating, deep penetration and moisture self-balance effects. However, non-uniform heating and sometimes runaway heating are still major problems with implementation of RF drying. RF-related combination drying takes advantages of both conventional drying methods and RF heating, leading to improved drying uniformity, better product quality and higher energy efficiency. This paper provides a brief introduction on the basic principle of RF drying, analyzes the RF heating and drying characteristics and examines recent literature on RF drying applications and possible methods for improving RF heating and drying uniformity. Recommendations for future research have been proposed to achieve practical and effective RF drying requirements and bridge the gap between academia and industry.