Antioxidant Activity of Phytochemicals from Distillers Dried Grain Oil

A distillate was obtained by molecular distillation of oil extracted from distillers dried grains (DDG). The distillers dried grain oil distillate (DDGD) contained phytosterols, steryl ferulates, tocopherols, tocotrienols, and carotenoids. DDGD was tested for its impact on the oxidative stability index (OSI) at 110 A degrees C of soybean, sunflower, and high-oleic sunflower oils, as well as the same oils that were stripped of their natural tocopherols and phytosterols. In addition, the impact of added DDGD on the stability of stripped sunflower oil during an accelerated storage study conducted at 60 A degrees C was also determined. DDGD (0.5-1% w/w) had little impact on the OSI of soybean, sunflower, and high-oleic sunflower oil, but at levels of 0.1-1% it significantly increased the OSI for stripped soybean, sunflower, and high-oleic sunflower oil in a dose-dependent manner. DDGD also delayed peroxide value, conjugated diene, and hexanal formation during accelerated storage of stripped sunflower oil. The antioxidant activity is probably due to the combination of tocopherols, tocotrienols, and steryl ferulates.