ABSTRACT
Radio-frequency (RF) heating generally refers to dielectric heating in nonmetallic materials caused by electromagnetic energy ranging between 10 and 300 MHz (Orfeuil, 1987). An industrial heating system operating in the ISM (Industrial Scientific Medical) frequency bands at 13.56, 27.12, or 40.68 MHz (Table 1) is a well-established method for processing various types of nonfoodmaterials, including textile and paper drying, plastics welding, and curing glue in plywood. Industrial applications can also be found in the drying operations for food products, e.g., drying bakery products after the baking process. In spite of the obvious advantages of RF heating such as deeper penetration ofRF energy in foods, simpler system configurations, and higher electricity to electromagnetic power conversion, compared to microwave heating, RF heating remains little known in the food science and food engineering research communities. This chapter gives a general introduction to the principle and systems of RF heating, and presents an overview of RF research in food processing and postharvest operations.
