Identification of alpha-tocopherol oxidation products in triolein at elevated temperatures.
The effect of high-temperature treatment on the stability of alpha-tocopherol (1) in triolein was assessed under a reduced-pressure atmosphere (4-40 mbar) simulating the deodorization step of the refining of vegetable oils. A marked degradation of 1 was observed, which increased with increasing temperature (180-260 degrees C) and heating time (20-80 min). The degradation of 1 in triolein at 240 degrees C was inhibited by the addition of the synthetic antioxidant TBHQ or when heating was performed under nitrogen atmosphere, indicating oxidative degradation. The oxidation products were isolated and identified as alpha-tocopherolquinone (2), 4a,5-epoxy-alpha-tocopherolquinone (3), and 7,8-epoxy-alpha-tocopherolquinone (4).
Verleyen
T
T
Department of Organic Chemistry, Coupure Links 653, 9000 Gent, Belgium. tom.verleyen@rug.ac.be
Verhe
R
R
Huyghebaert
A
A
Dewettinck
K
K
De Greyt
W
W
D000975:Antioxidants; D005511:Food Handling / Q000379:methods; D006358:Hot Temperature; D006873:Hydroquinones; D010084:Oxidation-Reduction; D010938:Plant Oils; D013816:Thermodynamics; D014304:Triolein / Q000737:chemistry*; D014810:Vitamin E / Q000737:chemistry*
D000975:Antioxidants; D006873:Hydroquinones; D010938:Plant Oils; D014304:Triolein; D014810:Vitamin E; C018855:2-tert-butylhydroquinone