Enhanced extraction of natural pigments from Curcuma longa L. using natural deep eutectic solvents

Natural deep eutectic solvents (NADESs) formed by organic acids and sugars were tested for their effectiveness in extracting the natural pigments called curcuminoids. Under optimum conditions (50 degrees C temperature, 0.1/10 g/mL solid/liquid ratio, and 30-minute extraction time), higher extraction yields were obtained when the solvent with 1:1 citric-acid-to-glucose ratio and 15% water (CGH) was used, as compared with conventional extraction solvents. Moreover, we studied the target curcuminoids antioxidant activities and stabilities in different solvents. Lastly, we demonstrated that solid phase extraction was an effective approach to recycle the natural pigments in the extracts. These results indicate that the proposed method is an excellent alternative for the extraction of natural pigments because it is environmentally friendly and can promote sustainability.