Free radical generation assays: new methodology for accelerated oxidation studies at low temperature in complex food matrices.

A novel method for the rapid screening of antioxidant efficacy and oxidative stability in food and feed matrices has been developed. The analyses are described as free radical generation (FRG) assays. The new procedure combines the use of azo-initiators with analytical equipment that is widely used for antioxidant research such as the oxidative stability instrument and the oxygen bomb.

Modeling of alpha-tocopherol loss and oxidation products formed during thermoxidation in triolein and tripalmitin mixtures.

The degradation of alpha-tocopherol and the formation of alpha-tocopherol and triacylglycerol oxidation products at high temperatures (150-250 degrees C) over a heating period (0-4 h) for a model system ranging between triolein and tripalmitin were modeled by use of an experimental design. The oxidation products of alpha-tocopherol formed under these conditions were alpha-tocopherolquinone (1 .4-7.

Gas chromatographic characterization of vegetable oil deodorization distillate.

Because of its complex nature, the analysis of deodorizer distillate is a challenging problem. Deodorizer distillate obtained from the deodorization process of vegetable oils consists of many components including free fatty acids, tocopherols, sterols, squalene and neutral oil. A gas chromatographic method for the analysis of deodorizer distillate without saponification of the sample is described.

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.