Quantitative high resolution13C nuclear magnetic resonance of the olefinic and carbonyl carbons of edible vegetable oils

The acyl distribution and acyl positional distribution (1,3-acyl and 2-acyl) of triacylglycerols derived from edible vegetable oils has been examined by¹³C nuclear magnetic resonance (NMR) spectroscopy. The acyl profile of three natural oils (corn, peanut, canola) and one specialty oil (high oleic sunflower oil, Trisun^® 80) has been defined from the high resolution (medium field 75.4 MHz) spectrum of the carbonyl and olefinic regions. The quantitative integrity of the NMR derived acyl profile is substantiated by gas chromatographic (GC) analysis. The positional distribution data of the three natural oils indicates that polyunsaturates are replaced in the 1,3-glycerol position exclusively by saturates, while the oley distribution remains, for the most part, randomly distributed. The same is not true for Trisun^® 80, which shows a more random distribution of the linoleyl groups as well.