Oxidative stability of crude mid-oleic sunflower oils from seeds with high γ- and δ-tocopherol levels

In this study, mid-oleic and high-oleic sunflower seeds were developed with high levels of gamma- and delta-tocopherols by traditional breeding techniques. Sunflower seeds containing various profiles of tocopherols, ranging from traditional high alpha, low gamma, low delta relative to those with high gamma, high delta, and low alpha, were extracted, and the crude oil evaluated for oxidative stability. After aging at 60 degrees C, oils were measured for peroxide value and hexanal as indicators of oxidation levels. We found that when the gamma-tocopherol content of mid-oleic sunflower oil (MOSFO) (NuSun) was increased from its regular level of 20 to 300-700 ppm, the oxidation of the oil was decreased significantly compared to MOSFO with its regular low gamma-tocopherol level. The modified oils had alpha-tocopherol contents of up to 300 ppm without negatively affecting the stability of the oil. An oil with one of the best oxidative stabilities had a tocopherol profile of 470 ppm gamma, 100 ppm delta, and 300 ppm alpha, indicating that MOSFO could be more oxidatively stable and still be a good source of Vitamin E from alpha-tocopherol.