Pure Sucrose Octaesters (SOE) and Triacylglycerols (TG) with the same fatty acid composition were oxidized at 100°C for 3, 6 and 12 h, in triplicate. Quantification of oxidized substrates and oxidized fatty acids was carried out by a combination of adsorption and size exclusion chromatographies. Induction time periods, peroxide values and changes in fatty acids were also determined. The results indicated that triacylglycerols were oxidized more rapidly than sucrose octaesters. No prooxidant effect of triacylglycerols on the oxidation of sucrose octaesters was found when a mixture (1:1) of both of them was subjected to oxidation. This work was supported by CICYT (Project ALl 88-0208). Peer reviewed