Porównanie metod przygotowania estrów metylowych kwasów tłuszczowych wg AOAC oraz metodą bezpośrednią przy oznaczaniu składu kwasów tłuszczowych tkanki mięsnej ryb

Abstract

Analysis of the composition of lipids is done by separating fatty acids (FA), most often through gas chromatography, after converting FA into their volatile derivatives: fatty acid methyl esters (FAME). The aim of the paper was to compare the results of analysis FA composition of three species of oily fish, both raw and subjected to heat treatment, by converting FA into FAME applying the AOAC method, and using the direct method. FAME were separated by gas chromatography-coupled mass spectrometry (GC-MS). It was shown that, in fish subjected to heat treatment, the percentages of EPA and DHA whose FAME were prepared via the direct method were 5-10% higher than in case of applying the AOAC method. As far as uncooked oily fish are concerned, the method of obtaining FAME had no relevance to the composition of fatty acids. The method of obtaining FAME can have a substantial impact on the percentages of individual acids or acid groups in fat, and, in turn, on results of evaluation its nutritional value.