Supercritical CO2 extraction of turmerones from turmeric and high-pressure phase equilibrium of CO2 + turmerones

This work studies the enrichment of turmeric α-β-Ar turmerone using supercritical fluid extractions followed by solid–liquid column partition fractionation. The high-pressure vapor–liquid phase equilibrium of the α-β-Ar turmerone with carbon dioxide was also examined. The purity of α-β-Ar turmerone was increased from 67.7% in extracted oil up to 91.8% in enriched oil, as determined by HPLC analysis. An equilibrium apparatus that comprises two vibrating tube densitometers was then adopted to obtain vapor and liquid equilibrium data for this asymmetric system of α-β-Ar turmerone and carbon dioxide mixture at 313.15 K and 333.15 K. Pressures ranged from 2.82 MPa to 20.80 MPa. Experimental data at elevated pressures were successfully correlated with theoretical methods of Peng–Robinson, Soave–Redlich–Kwong and Patel–Teja equations of state, individually combined with quadratic, Panagiotopoulos–Reid and Adachi–Sugie mixing rules.