Extraction of sage oil by supercritical CO2: Influence of some process parameters

Dried sage leaves (Salvia Officinalis L.) were used as a model matrix for supercritical-fluid extraction of essential oils with CO2. The influence of process parameters, such CO2 density and extraction time, on the composition of the extracts was studied. A balance between CO2 solvent power and selectivity was required to optimize sage oil composition. Moreover, to obtain essential oil, the supercritical-fluid extraction products were fractionated in two separators operated in series, This procedure was required to eliminate coextracted products like cuticular waxes. The extraction time proved to be one of the main parameters that determine the composition of the oil extracted. Indeed, lower-molecular-weight and less polar compounds were more readily extracted since the other families of compounds exhibit higher diffusion times. The oil extracted also contained small quantities of water. The water yield was measured and the possible role of water in the extraction process is discussed.