Characterization of the oxidation of rapeseed and butter oil triacylglycerols by four analytical methods

The aim of this study was to compare and evaluate four analytical methods in order to characterize oxidation of highly different triacylglycerols (TAG). Rapeseed oil (RO) TAGs, butter oil (BO) TAGs and their I:I (w/w) mixture were oxidized in the dark at 40 degrees C. Oxidation was followed by peroxide value (PV), anisidine value (AnV), O-2 consumption measurements, and analyses of volatile aldehydes. Based on measurements of PV and O-2 consumption, RO TAGs oxidized more than BO TAGs, whereas more volatile aldehydes were produced by BO than RO TAGs. The mixture was the most stable material. Analyses of volatile aldehydes proved to be important because characteristic profiles were formed both for RO and BO TAGs. Statistical analysis showed that when only one TAG material was studied, all four analytical methods were highly significantly correlated and could be replaced with each other. The correlation coefficients were much poorer when the results of all the TAG materials were combined. This study showed that it is necessary to use several analytical methods to compare and sufficiently characterize oxidizability of TAGs with variable fatty acid compositions. (C) 1997 Academic Press Limited.