Submitted to: Phytochemical Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 6, 1999
Publication Date: N/A
Interpretive Summary: Cedarwood oil extracted from various species of junipers is of high value and finds specialized uses as a perfume ingredient, odorant, and pest control agent. Cedar is also considered an unwanted species on animal grazing lands in some parts of the United States and is routinely removed for this purpose. The wood is frequently harvested and the low level of oil content extracted using hot water. This has proven to be an ineffective extraction method resulting in low yields and destruction of some of the oil components. In this project, extraction of the oil from cedarwood has been accomplished using a pressurized gas, carbon dioxide. This extraction agent is environmentally friendly and does degrade the oil components during the extraction process. In addition, a much higher yield of the oil is obtained that has an aroma more typical of cedar than oil extracted by hot water. Through this research, an alternative processing technology has been developed which can be implemented in a rural environment, thereby adding economic value to rural communities, utilizing a waste plant material to yield a value added product.
Technical Abstract: The extraction of cedarwood oil (CWO) using supercritical carbon dioxide (SC-CO2) was investigated, including 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 utilized. The highest percentage contribution of thujopsene to the SC-CO2 CWO occurred at 1,500 psi and 70 deg C and 100 deg C. Essentially all of the CWO was extracted from the wood matrix in the first 5 minutes, however, complete extraction of water required ca. 25 minutes. The amount of CWO extracted decreased as the age of the cedarwood chips increased. This decrease was greatest for the more volatile hydrocarbon components, thujopsene and cedrene. The mean weight percent yields of CWO for steam distillation and SC-CO2 extraction were 1.3% and 4.4%, respectively. Experienced analytical sensory panelist selected the SC-CO2 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-CO 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.