|Abidi, Sharon - RETIRED USDA-ARS|
Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2005
Publication Date: May 7, 2005
Citation: Rennick, K.A., Abidi, S., Warner, K.A. 2005. Effect of elevated temperatures on development of tocopherolquinones in oils. Annual Meeting and Expo of the American Oil Chemists' Society. p. 46. Technical Abstract: Few studies have reported the isolation and quantification of tocopherolquinone (TQ) in heated vegetable oils. Due to their antioxidant properties, quinones including tertiary butylhydroquinone (TBHQ), rosmariquinone and TQ are of great interest. We report results of studies in which the formation of TQ was followed in soybean oils with and without added alpha tocopherol (AT). Two hundred (200) mL of soybean oil (SBO) was spiked with 1500ppm AT then heated to 180 deg C. Aliquots were taken in 10 h increments from 0 to 40 hr. A second study utilizing 200 mL SBO without added AT was heated to 180 deg C. Aliquots were taken every 10 h from 0 to 55 hr. Two (2) gram duplicate samples were extracted with acidified hot methanol. These samples were analyzed by high-performance liquid chromatography (HPLC) utilizing an ODS-3 column and column splitter to scanning ultra-violet (UV) and fluorescence (FL) detectors. The mobile phase consists of 90:10 methanol: H2O to 100% methanol, with flow rate of 1 ml/min. In the spiked SBO, the AT levels slowly decreased from 1900ppm (0hr) to 1245ppm (30hr) followed by a dramatic decrease to 580ppm at 40hr. There was a corresponding linear increase of AlphaTQ levels from 130ppm to 600ppm (10 to 40hr). In the SBO study without added AT, 0 hr AT levels of 200ppm decreased to 66ppm at 35hr with none detected at 45 and 55 hr. AlphaTQ was detected at 15 hr (93ppm), 25 hr (124ppm), and 35 hr (112ppm).