Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 4/28/1996
Publication Date: N/A
Technical Abstract: The effects of tocopherol ratios on the oxidative and odor stability of purified oils were studied by measuring peroxides, headspace volatiles and odor characteristics of the oils after oil storage at 7500 lux at 30 deg C and in the dark at 60 deg C. Oils were stripped of minor constituents by passing the oils through columns of activated alumina and activated charcoal with ethyl ether and then deodorized. Pure tocopherols--alpha, gamma, and delta--in various ratios of low to high levels were added to the stripped oils. Stripped soybean oil samples aged 2 days at 60 deg C and containing low levels (20 ppm) of delta tocopherol had significantly higher peroxide values and hexanal levels than oils with high levels (200 ppm) of delta tocopherol. These results were not affected by the levels of alpha or gamma tocopherols used in the ratios. A trained analytical sensory panel, experienced in rating oxidized oils, evaluated the odor characteristics of the oils. The procedure developed to evaluate the odor of small quantities of oil consisted of placing 0.25g of oil on a 9 cm diameter sheet of filter paper in a 250 ml wide-mouth glass jar and closing the jar with a screw cap. Panelists found that the oils aged for 2 days at 60 deg C had significantly lower rancid odor intensities when 200 ppm of delta tocopherol was included in the tocopherol ratio than when only 20 ppm was added.