QUANTITATION OF OXIDIZED TRIGLYCERIDE MONOMERS AND DIMERS AS AN USEFUL MEASUREMENT FOR EARLY AND ADVANCED STAGES OF OXIDATION

Quantitation of oxidized triglyceride monomers and dimers is reported as a good measurement for early and advanced stages of oxidation. Appl icability of this approach to follow-up oxidation was tested in sample s of trilinolein and methyl linoleate stored at either room temperatur e or 60 degrees C for different periods of time. Oxidized monomers, di mers and polymers were determined in 50 mg-samples by adding monostear in as internal standard and applying a combination of adsorption chrom atography, using silica cartridges, followed by high-performance size- exclusion chromatography. Additionally, peroxide values and tocopherol contents were measured. Results showed that a significant rise of dim eric compounds denoted the end of the induction period while oxidized monomers were the only group of compounds showing a progressive increa se during the early stages of oxidation.