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 Characteristics of Ratite
Oils
E. Hernandez
Food Protein R&D
Center
Texas A&M University
Excerpts
from the American Oil Chemist
Society
Newsletter on
Ratites
Currently there are three
major species of birds from the ratite family
being raised in the US, namely ostrich, emu, and
rhea. These birds are produced primarily
for their meat, oil, and leather. Currently the
main market for ratite oils is in cosmetics.
Examples of some commercial products from ratite
oils include moisturizing creams, body lotion,
soap, and lip balm.
Most of the
published data on ratite oil is on the emu. The
main cosmetic and pharmaceutical properties
assigned to this oil are skin penetrating,
moisturizing, anti-arthritic and
anti-inflammatory properties. Work done in
Australia by Ghosh et. al., 1995 reported emu
oil, in combination with ethyl salicylate,
isopropyl salicylate and oil of eucalyptus, to
have anti-inflammatory, anti-arthritic activity
when tested in laboratory rats with induced
polyarthritis. Emu oil is also reported by these
workers to suppress human granulocyte elastase,
a tissue degenerative enzyme that is released
when tissue inflammation occurs. Zemstov et al.
(1995) reported a double blind study on the
moisturizing and cosmetic properties of emu oil,
noting that emu oil had skin permeability and
moisturizing properties superior to mineral oil.
Holick and Kinney (1996) reported that emu oil
increased the proliferation of cells and the
growth of hair follicles in lab rats. They also
reported that some of the cosmetic properties of
the oil appear to be synergistically increased
when used in combination with phospholipids from
other oils used in cosmetics such as palm,
sesame, safflower, borage and
coconut.
The oils
obtained from all three species of ratites,
namely emu, ostrich and rhea appear similar in
their basic composition. These oils are
triglecerides composed mostly of oleic,
palmitic, stearic and linoleic fatty acids. The
proportions of these fatty acids will vary
somewhat according to the type of bird and the
type of feed. Even though the relationship of
animal feed and oil compositions has not been
studied in depth, it is likely that the degree
of saturation of the fatty acids will be
affected by the type of fats in the animal feed
to a certain extent. There is a need for studies
to determine the metabolic parameters with
regard to fat amount and optimum concentration
of what are considered essential fatty
acids.
Ratite oils, after
extraction and processing, tend to separate into
two distinct phases, a liquid phase, i.e., olein
fraction and a solid phase, stearin. The
formation of stearin is due to the presence of
saturates (mostly palmitic acid) in the oil
which, as they conglomerate into crystals,
produces this solid phase. The crystallized emu
oil has a 'pearly' white appearance and
the liquid fraction or olein is transparent. As
expected, the strearin fraction is richer
in the more saturated fatty acids, namely
palmitic and stearic acids, and the olein
fraction is higher in oleic and linoleic
acids.
The rationale to use certain
oils in cosmetics is usually based on the belief
that triglyceride oils with fatty acids similar
in composition to the human skin will have
beneficial cosmetic properties. This not
entirely true. The major components of sebaceous
lipids are 45 - 60% triglycerides, 25% wax and
sterol esters, 12-15% squalene and 10% free
fatty acids (Lampe, 1983; Jass and Elias, 1991).
However, triglycerides are indeed the most
abundant component in the lipids of the human
skin and fatty acid components in emu oil are
similar to the fatty acids in the human stratum
corneum (outer layer of the skin) (Holick and
Kinney, 1996) even though their ratios are
different. Triglyceride oils rich in oleic and
linoleic acids such as olive and corn oil have
been widely used in cosmetics for some
time.
References
--Holick, M. F.
and Kinney, J. F. 1996. Drug and Cosmetic
Industry, January, 36-41.
--Ghosh, P.,
Whitehouse, M., Dawson, M., and Turner, A.
G. 1996. US Patent 5,431,924
--Prokop, W. H.
1985. JAOCS. 62(4), 805-811.
--Jass, H. E.
and Elias, P. M. 1991, Cos. Toil., 106(X).
47.
--M. A. Lampe. 1983. J. Lipid Research,
24, 131.
--Knowlton, J. and Pearce, S. 1993.
Handbook of Cosmetic Science and Technology.
Elsevier Editorial, Oxford, UK.
Photo
courtesy of Emu Today and
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