Microwave assisted extraction of curcumin by sample–solvent dual heating mechanism using Taguchi L9 orthogonal design

The present work reports on a novel extraction method using microwaves based on solvent–sample duo-heating synergism, for the extraction of curcumin from Curcuma longa L. The duo-heating mechanism is based on simultaneous heating of sample matrix and extracting solvent under microwave energy. Methanol soaked plant material was used as a modifier to bring about selective and effective heating of the sample under microwave. Acetone was used as the extracting solvent, which has excellent curcumin solubilizing capacity and heats up under microwave owing to its good dissipation factor. Extraction conditions, namely microwave power, irradiation time, particle size and modifier volume were optimized using Taguchi design approach and curcumin was quantified using high performance thin layer chromatography. The optimum conditions as obtained from signal-to-noise ratio analysis and interaction studies between factors were as follows: 20% microwave power, 4 min irradiation time, particles screened through sieve 20 and 8 ml of modifier. Microwave assisted extraction (MAE) under the influence of dual heating mechanism showed better precision and dramatically higher yield with significant reduction in extraction time under optimum extraction conditions, when compared to conventional approaches.