THE COMPOSITION OF HYDROGENATED FATS BY HIGH-RESOLUTION C-13 NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY

The high-resolution C-13 nuclear magnetic resonance spectra of twelve hydrogenated fats have been examined. Each spectrum contains 50-100 signals and reveals much about the nature of the acyl chains of both double-bond position and configuration. The signals for the omega1, omega2 and omega3 carbon atoms give information on the cis and trans isomers of the DELTA15, DELTA14, DELTA13 and DELTA12 18:1 esters, respectively. Allylic signals distinguish between cis and trans esters, and the proportion of total cis to total trans isomers can be obtained from these. Olefinic signals are the most informative, and most of these have been assigned. This leads to a semi-quantitative estimate of the various 18:1 isomers present. Assignments are based mainly on information already in the literature, but some were confirmed after urea fractionation of the acids from a hydrogenated oil in which cis and trans monoene acids were separately concentrated.