Capillary supercritical fluid chromatography-Fourier transform infrared spectroscopy study of triglycerides and the qualitative analysis of normal and “unsaturated” cheeses

Abstract

Capillary supercritical fluid chromatography (cSFC)-Fourier transform infrared spectroscopy (FT-IR)-flame ionization detection (FID) has been used to examine the separation of a synthetic mixture of saturated triglycerides. A careful study of the on-line FT-IR spectra of the separated components revealed that relative absorption intensifies of the infrared peaks corresponding to the antisymmetric CH 2 stretching and carbonyl (CO) stretching modes were related to the carbon number of an individual triglyceride. A comparison of the FT-IR spectra obtained in cSFC-FT-IR-FID separations of a cheese said to be high in unsaturates (“Flora” cheese) and a cheddar cheese showed that the Flora cheese does indeed contain only unsaturated triglycerides. The cheddar cheese contained many more triglyceride components, most of which correspond to saturated species. Comparison with the synthetic saturated triglyceride mixture showed that the speciation of some of the cheddar cheese components can be carried out.