Optimization of ionic liquid-based microwave-assisted extraction technique for curcuminoids from Curcuma longa L.

Abstract Ionic liquid-based microwave-assisted extraction was successfully applied for extracting curcuminoids from Curcuma longa L., and the antioxidant value of the extract was determined by DPPH and TRAP methods Response surface methodology was used to optimize experimental conditions for extraction yield and antioxidant value. The results indicated that the optimal extraction solvent was 0.3 mol/L 1-octyl-3-methylimidazolium bromide. Considering extraction yield as the reference index, the optimum conditions were as follows: extraction temperature 55 °C, extraction time 8 min, and solid-liquid ratio 0.5/30 (g/mL). Considering antioxidant value as reference index, the optimum conditions were as follows: extraction temperature 70 °C, extraction time 2 min, and solid-liquid ratio 0.5/30 (g/mL). Under optimum conditions (extraction yield as reference index), the average yield of three kinds of curcuminoids was 1.77%. Compared with ultrasound-assisted extraction, microwave-assisted extraction is a highly efficient and pollution-free method, which requires a shorter extraction time and less energy consumption.