Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

This contribution provides basic data for developing an extraction process for carotenoid compounds in terrestrial and marine plants with supercritical CO2 (SC-CO2). Specifically, the solubility (y2, molar fraction) of lycopene and astaxanthin was measured in SC-CO2 as a function of temperature (313 K ? T ? 333 K) and pressure (10 MPa ? P ? 42 MPa). Experimental data were correlated using a density-based model valid for a solvent density above 330 kg/m3. Based on this model and the best-fit model parameters, the solubility of lycopene in SC-CO2 at 313 K and 30 MPa (y2 = 0.40 * 10-6) was within a wide range of experimental values for the solubility of ?-carotene in CO2 under same conditions (0.20 * 10-6 ? y2 ? 0.50 * 10-6). The interpolated solubility of astaxanthin in SC-CO2 at 313 K and 30 MPa was slightly smaller (y2 = 0.19 * 10-6) than the one of lycopene, as expected for a slightly heavier and more polar solute. There was a larger increase in solubility of both lycopene and astaxanthin by increasing the temperature from 313 to 333 K at a constant pressure of 30 MPa (2.8 5.1 times) than by increasing the pressure from 30 to 50 MPa at a constant temperature of 313 K (1.3 1.6 times), which was consistent with the trend in literature for the solubility of ?-carotene in SC-CO2.