Extraction Process Optimization of Curcumin from Curcuma xanthorrhiza Roxb. with Supercritical Carbon Dioxide Using Ethanol as a Cosolvent

Curcuma xanthorrhiza Roxb., known as temulawak, Javanese ginger, or Javanese turmeric, is a plant species belonging to the ginger family. This plant originated in Indonesia, more specifically on Java Island, and is usually used as medicine. It contains a high amount of a phenolic compound, namely, curcumin. A supercritical carbon dioxide extraction technique was employed to extract curcumin from C. xanthorrhiza. The objective of this work was to investigate the effects of temperature, pressure, and CO₂ flow rate on the extraction yield and curcumin recovery from C. xanthorrhiza, which was extracted using supercritical carbon dioxide and ethanol as a cosolvent. The Box-Behnken design (BBD) experimental design and response surface methodology were used to optimize the extraction yield and curcumin recovery. The extraction conditions at a temperature of 40 °C, a pressure of 25 MPa, and a CO₂ flow rate of 5.34 mL/min produced the optimum extraction yield of 10.4% and curcumin recovery of 3.2%. From Fourier transform infrared analysis, although the physical-chemical structure in the residue of the starting material was almost similar, the quantity of all functional groups in the residue decreased from the starting material. From scanning electron microscopy analysis, it was confirmed that the cell was broken due to the high-pressure effect, so that the extraction process runs easily.