Author
 |
Abidi, Sharon |
|
Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/20/2003 Publication Date: 4/20/2003 Citation: Abidi, S.L. 2003. Tocol-derived minor constituents in selected plant seed oils. Journal of the American Oil Chemists' Society. 80:327-333. Interpretive Summary: Tocols are fat-soluble vitamin E compounds. These substances are important minor constituents of grains and oilseeds. They provide many health benefits and are useful in oil preservation. Determinations of the distribution of these compounds in oils are needed for studying the impact of the minor constituents on the quality and stability of vegetable oils. The content of vitamin-E active compounds in various oils were evaluated by high-performance liquid chromatography. A new system was used to eliminate the use of hazardous solvents. Vitamin E distribution data provide useful information on factors affecting oil quality/stability. Oil processors and food manufacturers will be able to use this information to select oils that are rich sources of vitamin E minor constituents in order to provide more healthful and better tasting oils for consumers. Technical Abstract: Various crude and processed seed oils were analyzed for tocopherols (T) and tocotrienols (T3) by reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection (FL). The oils include processed canola oil, crude corn oil, crude milkweed oil, crude palm oil, crude/processed rice bran oils, crude/processed soybean oil, crude/processed sunflower oil and related modified oil varieties. The HPLC system consisted of a pentafluorophenylsilica (PFPS) column and a mobile phase of methanol and water. The results of comparative methodological studies with rice bran oils and milkweed oils indicated that the reversed-phase PFPS-HPLC method in conjunction with the use of less hazardous solvents proved to be superior and a viable alternative to the conventional normal-phase HPLC method. Unlike the traditional nonpolar octadecylsilica phase failing to resolve beta-gamma pairs of T and T3, HPLC with the unique polar PFPS column enabled separations of all compounds of interest. Except for palm oil, beta-T and gamma-T were detected in all other crude oils. While most milkweed oils contained moderate levels of beta-T and gamma-T, the beta-T species was present in relatively low abundance in edible oils despite the observation of fairly high concentrations of gamma-T in the latter oils. Beta-T3 and gamma-T3 were detected along with alpha-T3 and delta-T3 only in palm and rice bran oils. Tocol-derived antioxidant distribution data for zero-time processed oils provided potential utility in correlation studies of frying quality and stability. The variable distribution data for crude oils shed some light on market profitability of oilseeds with rich sources of vitamin-E related minor constituents. |
