Abstract

In this study, a microwave extractor was successfully developed by simulating the waves and electric fields in a heating chamber. The chamber size and positions of the magnetrons were determined to maximize the heating in the microwave extractor. The results from the COMSOL Multiphysics software were used to construct the microwave extractor. Microwave-assisted solvent extraction was then performed on Kaempferia parviflora rhizomes. The highest total flavonoid and phenolic contents of 258.81 ± 1.01 µg quercetin equivalents per ml sample and 120.69 ± 0.75 µg gallic acid equivalents per ml sample, respectively, were achieved by extraction in methanol solvent at 83 °C within 2.5 min. These values were higher than those obtained from ultrasound-assisted extraction for 30 min and Soxhlet extraction for 60 min. In addition, the extraction time of 5,7-dimethoxyflavone using the Soxhlet extractor, which was approximately 1 h, was reduced to 2 min using the microwave extractor. These results demonstrated that microwaves are an outstanding heat source for extracting bioactive compounds and exhibit potential for commercial applications. Computer simulations were performed to provide insights into microwave heating. This information could be used to overcome technical challenges in industrial processes.