Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 1998
Publication Date: N/A
Technical Abstract: The effects of fatty acid triacylglycerol (TAG), fatty acid location (TAG structure), and TAG composition on the oxidative stability of soybean oil, before and after chemical randomization, were determined from genetically modified soybean varieties. These oils that have high content of saturated fatty acids (stearic and palmitic) are being investigated for food formulations such as margarine. Purified oils were oxidized neat under static oxygen headspace in the dark at 60C. This accelerated oxidative stability test permitted investigation of soybean oil deterioration at oxidation parameters appropriate to oil storage conditions. Soybean oil oxidation was monitored by peroxide value and by formation of TAG total oxidation products, monohydroperoxides, secondary oxidation products and oligomers. Oxidation results indicated that oxidative stability was positively affected by three types of oil modification: a) fatty acid composition modification (decrease of readily oxidizable fatty acids such as linolenic and linoleic and increase of oxidation resistant fatty acids such as oleic, stearic and palmitic); b) TAG structure modification (increase in oleic and decrease in linoleic at the glycerol moiety carbon 2); and c) TAG composition modification (decrease in linolenic and linoleic containing TAG and increase in TAG with stearic and palmitic acids in combination with oleic acid).