Position Distribution Study of α(1,3)-acyl and β(2)-acyl of ω-3 Fatty Acids in Cod Liver Oil by ¹³C-NMR

OBJECTIVE The position distribution α (1,3)-acyl and β(2)-acyl of ω-3 fatty acidsmoroctic acid (C18:4 n-3, MA), eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid(C22:6 n-3, DHA) in the form of triacylglycerols in cod liver oil have been examined by ¹³C-NMR. METHODS The samples were directly determinated with dissolving in CDCl₃ by high resolution ¹³C-NMR spectroscopy. RESULTS The ¹³C NMR-derived data of the position distribution α(1,3)-acyl and β(2)-acyl for MA, EPA and DHA in δ 171.5-173.5 ppm were consistented with corresponding data reported in the literature. The characteristic peaks of ω-3 fatty acids in two batches cod liver oil were not detected, but that were measured in four batches of cod liver oil with different the position distributionβ(2)-acyl. According the ratio of the position distributionβ(2)-acyl, the more possibility of extracting from farmed fish in four batches of cod liver oil was found. CONCLUSION The method of ¹³C-NMR is simple and quick, which can identify good or bad quality of cod liver oil.