Posted by admin January 11th, 2011 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 Tomorrow
E. Hernandez