Supercritical carbon dioxide extraction of hazelnut oil

Solubility of hazelnut oil in supercritical carbon dioxide (SC-CO2) was determined at 15-60 MPa, and 40-60 °C. The crossover pressure of hazelnut oil was between 15 and 30 MPa. The solubility increased with pressure, but increased with temperature above the crossover pressure. Hazelnut particles (1-2 mm) were extracted at 30-60 MPa, and 40-60 °C with SC-CO2 flow rate of 2 ml/min. Extraction occurred in two periods. The released oil on the surface of particles was extracted in the fast extraction period, and 39% of the initial oil was recovered at each condition. However, the duration of the fast extraction period decreased with increased pressure and temperature. The unreleased oil in the intact cells was extracted in the slow extraction period. The maximum recovery was 59% at 60 MPa and 60 °C, for 180 min of extraction. The fluid phase and solid phase mass transfer coefficients increased with increased pressure and temperature.