Solubility of lycopene in supercritical CO<inf>2</inf> fluid as affected by temperature and pressure

For extraction efficiency, it is important to determine the lycopene solubility for optimum extraction technology and highest resulting yield. The temperature range of 50-80 °C and pressure range of 200-400 bars were used to measure the solubility of lycopene from tomato processing residue materials during supercritical fluid extraction. Single-pass flow method, off-line solute analysis, and subsequently HPLC quantitative analysis were the procedures followed for the lycopene extraction. The resultant calculated solubilities were on the lower scale as then ranged in the magnitude of 10-6. Under supercritical conditions, increasing solubility of lycopene is stimulated by an increase in temperature and pressure. The highest solubility obtained was 1.9 × 10-6 mol fraction at a pressure of 250 bars and at a temperature of 80 °C. Above these conditions, distinct signs of thermal degradation were observed. The efficiency calculated based on the experimental data was compared with the modified Peng-Robinson Equation of State. The correlated results through modelling show reasonably fair agreement with the experimental data. Through comparison of results produced by experimental methods and modelling, it was determined that the most favourable conditions for high solubility of lycopene in supercritical CO2, for this particular method of analysis, were at 60 and 70 °C. Crown Copyright © 2008.