Analysis of Edible Vegetable Oils by Infrared Absorption Spectrometry

Abstract

In order to explore the more suitable conditions for using the edible vegetable oil in daily life, the peak position, peak shape, peak intensity and peak area detected by Fourier transform infrared spectroscopy (FTIR) of four different kinds of edible vegetable oils without heated and heated beyond the temperature of the smoke point have been measured. By analyzing the relative intensities of the peak high of the characteristic absorption peaks and the relative changes of the peak areas of the characteristic absorption peaks, it is found that the unsaturated fatty acids, trans fatty acids, the degree of unsaturation and other indicators of the oil heated beyond the temperature of the smoke point have been changed obviously. Aiming at index changes in the four kinds of edible vegetable oils, it is shown that both the relative contents of unsaturated fatty acids and the degree of unsaturation decrease at different extent for each oil, while the trans fatty acids increase at different extent for each oil. These changes reflect that the nutritional value of the vegetable oil has been greatly reduced and long-term ingestion will bring in adverse effect to human health when heated beyond the temperature of the smoke point. The obtained results are significant to correctly use the edible vegetable oil in everyday life.