Supercritical fluid extraction of peach (Prunus persica) seed oil using carbon dioxide and ethanol

Peach seed oil was extracted using supercritical CO2 at 40 and 51 °C and pressures of 15.0 and 19.8 MPa. Carbon dioxide modified with 2.5 and 5.0 mol% ethanol was also used in similar experiments. Two different extraction cells were used to analyze the effects of the cell size and the solvent flow rate on the initial extraction yield. At the optimum conditions, the extraction yield was 70% of that obtained by a Soxhlet extraction in liquid hexane. Low solvent flow rates allowed the determination of the oil solubility in pure carbon dioxide at the conditions of temperature and pressure of supercritical fluid extractions. The extracted peach oils were characterized with respect to fatty acids and tocopherols content by CG and HPLC, respectively. No significant differences were observed in the composition among the oils obtained using supercritical CO2 or modified CO2 and the Soxhlet extraction using hexane. Upon further optimization, supercritical fluid extraction is shown to be a good alternative to conventional liquid extraction.