Raman spectroscopic analysis of the<i>cis/trans</i> isomer composition of edible vegetable oils

Abstract

Abstract A new method is presented for determining the cis/trans isomer content of edible vegetable oils. The intensities of Raman lines near 1656 and 1670 cm −1 are associated with the cis and trans configuration, respectively. A precision of ca. 1% can be obtained in the cis/trans isomer analysis of binary mixtures of methyl esters and triglycerides of monoenes and dienes and of hydrogenated vegetable oils. The spectroscopic data also provide the iodine value of vegetable oils or isolated fractions with precision for a single determination of ca. 1%.