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Essential
oils are the highly concentrated essences of aromatic
plants and are commonly used in aromatherapy, therapeutics,
flavours and fine perfumery. Essential Oils contain
the odorous principles of the plant material from which
they are derived, and all useful parts of the plant
may be utilized in their production. |
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| EXTRACTION
OF ESSENTIAL OIL: STEAM DISTILLATION
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Steam
distillation is the most common method of extracting
essential oils. Pressurized steam is generated in a
separate chamber from which it is circulated into a
still (a separate chamber) which contains water and
plant materials. The hot steam causes the walls of cells
in the plant that store the essential oil to open and
to release the oil. The released essential oil evaporates
and is carried by the steam into a condensation chamber
(cooling tank) where the steam cools. The steam is condensed
into water and the essential oils floats on the surface
of the water. The essential oil is skimmed off the water.
The remaining water is called floral water or hydrosol
which can also be used for various purposes. |
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| EXTRACTION
OF ESSENTIAL OIL: COLD PRESSING
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Cold
pressing or scarification is another method of extracting
essential oil. It is generally used to extract citrus
fruit oils such as grapefruit, lemon, lime, and tangerine
oils. In this process, the fruits are rolled over a
trough with sharp projections which penetrate the pulp
creating tiny openings in the pockets that contain the
essential oil. The fruit is then pressed in order to
squeeze the juice out of the pulp and the essential
oil out of the pockets. The essential oil rises to the
surface of the juice and is separated from the juice
by centrifugation. |
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LIST
OF REFERENCES: |
Lawless,
J. The Illustrated Encyclopedia of Essential
Oils - The Complete Guide to the Use of Oils in Aromatherapy
and Herbalism, Element, Shaftesbury, 1995 |
Medicinal
Plants of Nepal, His Majesty's Government of Nepal,
Ministry of Forest and Soil Conservation, Department
of Plant Resources, 6th Edition, Kathmandu, 2001 |
Sheppard-Hanger
Sylla, The Aromatherapy Practitioner Reference Manual,
Tampa, 1998 |
Newall,
C.A., L.A. Anderson and J.D. Phillipson. 1996. Herbal
Medicines: A Guide for Health-care Professionals. London:
The Pharmaceutical Press. |
Bisset, N.G. (ed.), Wichtle, M. 1994. Herbal Drugs and
Phyotopharmaceuticals: A Handbook for Practice on a
Scientific Basis. Boca Raton, Florida: CRC Press. |
