Sequential Microwave-assisted Extraction for Isolation of Quercetin from Red Kidney Bean

Quercetin is a biological flavonoid, which can be found in red kidney bean at high concentration. In this study, a comparison was conducted between traditional and modern extraction methods. Sequential microwave-assisted extraction was used for isolation of quercetin from red kidney bean. The effect of several factors such as particle size of grinded kidney bean, extraction solvent, microwave power and extraction time on the extraction yield of quercetin was considered. To analyze the quercetin, HPLC method was developed. The highest extraction efficiency was obtained (35.8 mg quercetin /g kidney bean) when 60 w/w% acetone used as the solvent. In addition, the solvent to solid ratio was 10:1 and the irradiation power of 800W was applied for the experiment duration of 1 min. Acquired extraction yield according to the current method was higher than extracted quercetin from soxhlet (24.6 mg quercetin /g kidney bean) and maceration (32.75 mg quercetin /g kidney bean). In the present study, quercetin was successfully extracted from kidney bean by microwave-assisted extraction. Quercetin structure remains intact and can be used to produce therapeutic compounds.