Detection and Identification of Natural Antioxidants in Edible Oils Using LC Fractionation with Off-Line Effect-Based Detection

Many edible oils contain natural antioxidants that protect the oil from lipid oxidation. Knowledge on the identity of these oxidation inhibitors is crucial for finding natural ways to protect healthy unsaturated fats and oils from turning rancid. In this article a new assay that allows rapid quantification of the lipid oxidation-inhibiting potential of pure compounds or liquid chromatographic fractions is described. The assay uses accelerated aging of docosahexaenoic acid ethyl ester (DHA-EE) to quantify the extent of oxidation and oxidation inhibition. In the assay fast gas chromatography is used to monitor the disappearance of the DHA-EE and the appearance of volatile oxidation products. The method is fast and allows multiple fractions to be tested in parallel.