Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2009
Publication Date: 7/1/2009
Citation: Moser, J.K., Vaughn, S.F. 2009. Antioxidant Activity of Phytochemicals from Dried Distillers Grain Oil. Journal of the American Oil Chemists' Society. 86:1026-1035. Interpretive Summary: Research has demonstrated that oil from dried distiller’s grains has valuable antioxidants that can prevent lipid oxidation and increase the storage stability of vegetable oils when added at relatively low levels. Oxidation negatively impacts the shelf-life and overall quality of vegetable oils and all foods that are made with fats or oils. A previous study conducted in our lab had shown that oil from corn dried distiller’s grains was high in natural phytochemicals, including antioxidants such as vitamin E. In this study, the phytochemicals were concentrated out of the DDG oil and then added to soybean, sunflower, and high-oleic sunflower oils. The phytochemical mixture improved the oxidative stability of these oils in a dose-dependent manner. It also improved the storage stability of sunflower oil. The antioxidant activity was determined to be due to more than one component in the mixture, including tocopherols, tocotrienols, and the ferulate phytosterol esters. This research demonstrates that oil from dried distiller’s grains has valuable antioxidants, and that these antioxidants can improve the oxidative stability of vegetable oils.
Technical Abstract: A distillate was obtained by molecular distillation of oil extracted from distiller’s dried grains (DDG). The dried distiller’s grains distillate (DDGD) contained phytosterols, steryl ferulates, tocopherols, tocotrienols, and carotenoids. DDGD was tested for its impact on the oxidative stability index (OSI) at 110 deg 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 deg 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 to 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 likely due to the combination of tocopherols, tocotrienols, and steryl ferulates.