A HIGH-RESOLUTION C-13-NMR STUDY OF VEGETABLE MARGARINES

High resolution nuclear magnetic resonance (NMR) spectra of edible mar garine triglycerides were recorded at a C-13 frequency of 100.64 MHz a nd high resolution conditions were set up for quantitative composition analysis. The C-13-NMR carbonyl resonances provide useful information on fatty acid composition and on the distribution of saturated and un saturated fatty acids in the alpha- and beta-acyl position of triacylg lycerols. Olefinic carbon resonances, as well as methylene signals, al low the total level of trans-fatty acids and individual isomer composi tion to be assessed. The beta-acyl distribution of saturated/unsaturat ed fatty acids and the trans-fatty acid content of margarines can be s imultaneously determined so that hydrogenated margarines can be distin guished from those produced using interesterification or cooling fract ionation processes. The reliability of high resolution C-13-NMR in mon itoring the manufacturing process of margarine and its quality control are discussed.