ASSESSMENTS ON THE DIGESTIBILITY OF OXIDIZED COMPOUNDS FROM [1-C-14]LINOLEIC ACID USING A COMBINATION OF CHROMATOGRAPHIC TECHNIQUES

The aim of this study was to evaluate the digestibility coefficients o f different groups of oxidized fatty acids by applying a methodology b ased on chromatographic techniques. After thermoxidative treatment, ox idized labelled linoleic acid was isolated and included at 1% in the e xperimental diets. Male 250-300 g Wistar rats were fed ad lib for seve n days. Lipids extracted from diets and faeces were analyzed using a c ombination of chromatographic methods and radioactivity measurements t o determine the specific digestibilities of four groups of altered fat ty acids: oxidized monomers, non-polar dimers, oxidized dimers and pol ymers. Mean digestibility coefficients of oxidized monomers, dimers an d polymers were 91.0, 74.5 and 69.8%, respectively. In contrast, non-p olar dimers were poorly absorbed. The presence of unaltered labelled f atty acids in faeces indicated that structural modifications may have been taken place prior to absorption, and oxidized fatty acids seem to be the main compounds affected.