Developing radio frequency heating treatments to control insects in mung beans

Abstract

Radio frequency (RF) treatments are often used for disinfestations while maintaining the quality of postharvest agricultural products. The purpose of this research was to determine the efficacy of RF treatments for disinfesting mung beans. A pilot-scale, 27 MHz, 6 kW RF unit was used to study the heating uniformity of 6.0 kg mung beans in three different packaging methods heated from 25 °C to 54 °C, and the quality of RF treated mung beans was evaluated. The results showed that the best treatment was achieved by using an eight-layer polypropylene packaging method, an electrode gap of 12.5 cm for heating 5 min, 54 °C surface forced air heating, and 6 min 54 °C forced air holding due to the low heating uniformity index. Then a single layer of forced room air was used for cooling to avoid quality degradation. There was no significant difference in the moisture content, water activity, protein, starch, germination rate, and color values of mung beans before and after RF treatments. Therefore, RF treatments may hold the potential for the effective disinfestations of mung beans.