Abstract

This contribution provides basic data for developing an extraction process for carotenoid compounds in terrestrial and marine plants with supercritical CO 2 (SC-CO 2). Specifically, the solubility (y 2, molar fraction) of lycopene and astaxanthin was measured in SC-CO 2 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/m 3. Based on this model and the best-fit model parameters, the solubility of lycopene in SC-CO 2 at 313 K and 30 MPa (y 2 = 0.40 × 10 -6) was within a wide range of experimental values for the solubility of β-carotene in CO 2 under same conditions (0.20 × 10 -6 ≤ y 2 ≤ 0.50 × 10 -6). The interpolated solubility of astaxanthin in SC-CO 2 at 313 K and 30 MPa was slightly smaller (y 2 = 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 β-carotene in SC-CO 2. © 2006 Elsevier B.V. All rights reserved.