Edible oils:: discrimination by 1H nuclear magnetic resonance

The H-1 nuclear magnetic resonance (NMR) spectra of 36 edible oil samples of 15 different botanical origins were recorded with a 300 MHz instrument using deuterated chloroform as solvent. The assignment of each of their peaks was made by comparison with those of standard compounds, tristearin, triolein, trilinolein and trilinolenin. For the first time, certain spectral regions of interest, conveniently expanded, together with the chemical shifts of their peaks, are given for 15 oil samples of different botanical origin. The usefulness of each of these spectral regions in the differentiation of oils is discussed. It is shown that H-1 NMR spectra can be considered as the fingerprint of each oil sample. It is proved that they provide a great deal of information which permits discrimination between oils of different composition. This discrimination can be made in many cases with the naked eye by observation of certain spectral signals, without any other additional determinations. (C) 2003 Society of Chemical Industry.