Oxidative stability of natural and randomized high-palmitic- and high-stearic-acid oils from genetically modified soybean varieties

The oxidative stability of soybean oil triacylglycerols (TAG) obtained from genetically modified soybeans was determined before and after chemical ran domization. Soybean oil oxidative studies were carried out under static oxy gen headspace-at 60 degrees C in the dark and oxidative deterioration was m onitored by peroxide value, monomeric and oligomeric oxidation products, an d volatile compounds. Randomization of the soy bean oil TAG improved the ox idative stability compared to the natural soybean oil TAG. Oxidative stabil ity was improved by three factors. Factor one was the genetic modification of the fatty acid composition in which polyunsaturated acids (such as linol enic and linoleic acids) were decreased and in which monounsaturated fatty acids (such as oleic) and saturated acids (palmitic and stearic) were incre ased. Factor two was the TAG compositional modification with a decrease in linolenic and linoleic-containing TAG and an increase in TAG with stearic a nd palmitic acids in combination with oleic acid. Factor three was the TAG structure modification accomplished by an increase in saturated fatty acids and a decrease in linoleic and linolenic acids at the glycerol moiety carb on 2.