Isolation of rock rose essential oil using supercritical CO2 extraction

Supercritical carbon dioxide has been used as a solvent for the extraction of rock rose leaf (Cistus ladanifer L.). The aim of this work was to identi fy the best processing conditions to obtain rock rose essential oil. The op erating variables were selected so that the only extracted compounds were e ssential oils and waxes (8-10 MPa and 30-60 degreesC), avoiding the coextra ction of high-molecular-weight compounds that do not contribute to fragance formation. Moreover, a two-stage separation procedure was used to separate the waxes from the essential oil. The supercritical extracts were characte rized by gas chromatography (GC) to assess the presence of undesirable comp ounds and to obtain the detailed oil composition. The best oil was produced by extraction at 9 MPa and 40 degreesC and fractionation of the product in two separators in series operating at P = 7 MPa, T = -10 degreesC and at P = 2 MPa, T = -10 degreesC, respectively. Organoleptic analysis confirmed t he high quality of the product.