FATTY-ACID DISTRIBUTION BY C-13-NMR-SPECT ROSCOPY

In comparison to the conventional GC- or GC-MS analytics of triglyceri des and phospholipids the C-13-NMR-spectroscopy gives more detailled s tructure information. Without chemical derivatisation and standards it is possible to get qualitative and quantitative values of the total a nd the individual fatty acid distribution related to the position in t he glycerol back-bone. The complex C-13-NMR-spectra of known triglycer ides from different sources like plants, single cells and fish are com paired to assign the signals. The carbonyl-signals in the region betwe en delta = 171-173 ppm are well separated for fatty acids from Delta-4 to Delta-9-type and even for the saturated type. Using the methyl-sig nals a differentiation between omega-3 and omega-6-fatty acids is poss ible. Additionally the carbonyl-signals of fatty acids in sn-1/3 and s n-2 are separated. With knowledge of the fatty acid position in the tr iglyceride it is possible to classify oils or phospholipids for nutrit ion with respect to their usefulness in milk substitutes or baby food etc. The power of the method is demonstrated with the distribution of arachidonic acid (ARA) and docosahexaenoic acid (DHA) in egg yolk leci thin.