Supercritical carbon dioxide extraction of cedarwood oil: a study of extraction parameters and oil characteristics

The extraction of cedarwood oil (CWO) using supercritical carbon dioxide (SC‐CO2) has been investigated with respect to the effects of extraction temperature and pressure, length of extraction, and age of cedarwood chips. Steam distilled and SC‐CO2 derived CWOs were compared by gas chromatography and sensory evaluation. The extraction of CWO increased with extraction temperature, except at the lowest pressure utilised. The highest percentage contribution of thujopsene to the SC‐CO2 derived CWO occurred with the combination of 1500 psi and 70°C or 100°C. Essentially all of the CWO was extracted from the wood matrix in the first 10 min, however, complete extraction of water required ca. 25 min. The amount of CWO extracted decreased with increasing age of the cedarwood chips. This decrease was greatest for the more volatile hydrocarbon components, thujopsene and cedrene. The mean weight percentage yields of CWO for steam distillation and SC‐CO2 extraction were 1.3 and 4.4%, respectively. An experienced analytical sensory panel selected the SC‐CO2 derived CWO as being more similar to the original cedarwood chips than the steam distilled CWO. Volatile collections performed on SC‐CO2 extracted, steam distilled and unextracted cedarwood chips indicated that the SC‐CO2 extracted chips released almost no volatiles, whereas the unextracted chips released a higher amount of volatiles. The steam distilled cedarwood chips released an intermediate level of volatiles. Copyright © 2000 John Wiley & Sons, Ltd.