NEWS RELEASE:
Cedarwood Oil: Making It More Aromatic, More Available
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ARS News Service
Agricultural Research Service, USDA
June 17, 1999
Linda McGraw, (309) 681-6530, lmcgraw@asrr.arsusda.gov
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PEORIA, Ill., June 17--When you can't see the forest for the trees, focus on
the tree's valuable products.
That's the approach that scientists Fred Eller and Jerry King at the
Agricultural Research Service have taken in developing an environmentally
safe method to extract more and better quality cedarwood oil from juniper
trees.
The extraction method, known as supercritical fluid extraction (SFE),
already benefits consumers who drink decaffeinated coffee.
Cedarwood oil--used in cosmetics, perfumes, home odorants, and as an insect
control agent--is usually extracted from sawdust and wood chips by steam
distillation. But this extraction method produces low oil yields and often
decomposes the oil, causing it to have an off-odor. In lab tests, Eller
obtained 30 percent more oil than the yield from conventional steam
distillation without destroying the oil's aromatic components.
"Steam distillation doesn't penetrate deeply into chips, so it averages only
a 50 percent yield of the oil from the wood," said Eller, a chemist at ARS'
National Center for Agricultural Utilization Research in Peoria, Ill. The
presence of oxygen and high temperatures in steam distillation also erodes
oil quality.
But SFE, which uses carbon dioxide (CO2), works better "because it diffuses
in and out of the wood more easily than steam, carrying the cedarwood oil
with it. The CO2 is then easily removed from the extract when the mixture is
depressurized. This leaves a more pure oil that's uncontaminated by solvent
residue," Eller said.
Because SFE operates in an oxygen-free atmosphere, the oil's components
aren't degraded, making the cedar aroma more similar to the original wood
chips than the oil extracted by steam distillation. That's based on an odor
analysis by Peoria researchers.
On Western rangelands, where cattle and wildlife subsist on forage grass,
juniper trees and shrubs are unwelcome inhabitants. The reason: The trees
crowd out forage grasses and deplete the soil of water and nutrients needed
for other plants. In the Midwest and Southwest, farmers and cattle ranchers
routinely remove junipers from fields and ranges at significant expense.
Eller and King envision someday being able to develop a mobile SFE unit that
farmers could use to produce a value-added product. This could be an
economic boost especially for Midwestern farmers, where more land is being
invaded by junipers. Cedarwood oil is currently valued between $4.00 a pound
(for Texas oil) and $7.00 (for Virginia oil).
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Scientific contact: Fred J. Eller, Food Quality and Safety Research Unit,
ARS National Center for Agricultural Utilization Research, Peoria, Ill.,
phone (309) 681-6232, fax (309) 681-6340, feller@mail.ncaur.ars.usda.gov.
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