Comparison of oxidative resistance of traditional and high-oleic peanut oils in emulsions

Abstract

The oxidation rate of vegetable oils strongly depends on the content of polyunsaturated fatty acids, natural antioxidants and prooxidants. The resistance of oil against oxidation thus depends very much on the linoleic acid content. Virginia peanut oil (a traditional cultivar, containing 30% linoleic acid) was compared with SunOleic peanut cultivar (containing only 3% linoleic acid). The tocopherol content was rather similar in the two oil samples. Emulsions were prepared using soybean lecithin as an emulsifying agent. The formation of conjugated hydroperoxides was measured at 234 nm. The induction period differred very much in bulk oil, but only moderately in emulsions containing copper ions as prooxidants. The effect of copper ions on the rate of oxidation was lower in SunOleic oil emulsion, compared with the Virginia oil emulsion. Similarly, the effect of sage extracts on the resistance against autoxidation was higher in SunOleic oil emulsions than in Virginia oil emulsions.