Supercritical CO2 extraction of curcumins and essential oil from the rhizomes of turmeric (Curcuma longa L.)

Turmeric rhizomes were extracted with supercritical CO2 and supercritical C O2 + ethanol. Extraction experiments were carried out at pressures of 25 an d 30 MPa and temperatures of 313 and 318 K. The influence of the drying tem perature of the raw material on the extraction yield and curcuminoids profi le was evaluated. The higher content of curcuminoids in the extracts was ob tained by supercritical fluid extraction from rhizomes dried at 343 K using CO2 + ethanol. The identification of curcuminoids in both the extract and the residual solid was performed by both spectrophotometry and HPLC. The co mposition of the essential oil was determined by gas chromatographic mass s pectrometry. A mathematical model was used to describe the overall extracti on curves. The mass transfer inside the solid matrix was described by a lin ear first-order desorption model, whereas the transfer in the fluid phase w as described by a convective mass-transfer model. The mathematical model fi tted well the experimental data.