Optimization and comparison of three extraction methods of anthocyanin from Gynura bicolor

In this study, traditional water bath extraction method (WBE) , microwave-assisted extraction method (MAE) and ultrasonic-assisted extraction method (SAE) were adopted to extract anthocyanin from the leaves of Gynura bicolor (Roxb. ex Willd.) DC.respectively.0.6% citric acid was added to 20% ethanol as extraction solvent, and the optimal extraction conditions of WBE were as follows: the ratio of material to liquid was 1∶11 (g/m L) , the extraction temperature was 80 ℃, and the extraction time was 120 min.The yield of anthocyanin extract was 7.70% and the color value was 1.44.Meanwhile, the optimum extraction parameters of MAE were as follows: the ratio of material to liquid was 1∶7 (g/m L) , the power was 700 W, the extraction time was 2.0 min, the yield of anthocyanin extract was 6.65% and the color value was 1.26. Besides, the optimum extraction parameters of SAE were as follows: the ratio of material to liquid was 1∶11 (g/m L) , the power was 270 W, the extraction temperature was 80 ℃, the extraction time was 90 min, the yield of anthocyanin extract was 8.25% and the color value was 1.16.Among these three extraction methods, the MAE had the highest extraction efficiency, the SAE had the highest yield of pigment extract, and the WBE had the highest color value, however.