Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 21, 2003
Publication Date: May 25, 2004
Citation: Eller, F.J., Taylor, S.L. 2004. Pressurized fluids for extraction of essential oils from juniperus virginianna. Journal of Agricultural and Food Chemistry. 52(8)2335-2338. Interpretive Summary: Cedarwood oil from various species of junipers is a high value commodity and it finds specialized uses as a perfume ingredient, odorant and pest control agent. Cedars are also considered a pest species on animal grazing lands and is routinely removed to improve pastures. Cedarwood oil is generally obtained by steam distillation, however, this process is a relatively ineffective method for oil removal and also tends to degrade the cedarwood oil as well. In this project, the extraction of both cedarwood oil from cedar sawdust as well as the cedarleaf oil from the needles was accomplished using pressurized carbon dioxide. Carbon dioxide is an effective solvent, is environmentally-friendly and does not degrade the oil during the extraction process as does steam. Through this research, an alternative processing has been developed which can be implemented in a rural environment to utilize an abundant underutilized agricultural product.
Technical Abstract: The extraction of cedarwood oil (CWO) using liquid carbon dioxide (LC-CO2) was investigated, including the effects of extraction pressure and length of extraction. The chemical composition of the extracts were monitored over the course of the extraction as well. When 80 liters of carbon dioxide were used for the extraction of ca 10 grams of cedarwood chips, the overall yield of CWO varied very little from treatment to treatment, with all temperature/pressure combinations yielding between 3.4 to 3.7% CWO overall. The rate of extraction did vary for the various temperature/pressure combinations. At 25 C and 40 C, the extraction of CWO tended to increase with extraction pressure and temperature. At 70 C and 100 C, the rates of extraction were virtually identical. There was a slight difference in the chemical compositions of the fractions collected over the course of the extractions for extractions at 25 C compared to those done at 100 C. At 100 C, there tended to be a slight increase in the hydrocarbon, cedrene in conjunction with a decrease in the tertiary alcohol, cedrol. It appears that the higher temperatures cause a dehydration of cedrol to cedrene during the supercritical fluid extraction. The use of subcritical water was also investigated for the extraction of CWO as well. Although some CWO was extracted using this method, the temperature/pressure combinations which gave the highest weight percentage yields also gave oils with an off odor while those combinations which gave a higher quality oil had very low yields. Liquid and supercritical CO2 extractions of juniper leaves effectively removed juniper leaf oil and gave an oil similar in chemical composition to leaf oils derived by steam distillation.