Characterization of edible oils and lard by Fourier transform infrared spectroscopy. Relationships between composition and frequency of concrete bands in the fingerprint region

Fourteen samples of edible oils and lard have been studied by means of Fourier transform infrared spectroscopy. The spectra were recorded from a film of pure oil or lard between two discs of KBr. The bands of the spectra were assigned to different functional group vibrations. The frequencies of some bands have constant values, independent of the nature of the sample. However, frequencies of other bands, some of them in the fingerprint region, depend greatly on the sample composition. Equations obtained from frequency of these bands and composition data are valuable to predict the proportions of saturated, monounsaturated and polyunsaturated acyl groups in oils and lard.