Fractionation of acid lime essential oil using ethanol/water mixtures: effect of the process on the aroma profile

This study aims to separate aroma-active components of the crude Citrus latifolia essential oil (EO) from the unstable terpene hydrocarbons using ethanol/water mixtures through liquid–liquid equilibrium (LLE) and to evaluate the aroma profiles of the crude EO and the LLE phases. For this purpose, the liquid compositions of the crude EOs and the LLE phases were found by gas chromatography analysis. The compositions of the liquid phases were predicted using the NRTL model and compared to the experimental data. Afterwards, the concentrations of the components in the vapour phases above the liquid mixtures were obtained by headspace analysis and the odour intensity of each component was estimated using the Stevens’ power law concept. Finally, the classification into olfactory families was evaluated through the Perfumery Radar methodology. The solvent extraction technique made it possible to obtain extract phases enriched in citral and poor in monoterpenes, with aromas profiles similar to that of the crude EO and classified as herbaceous and citrus scent, with floral, woody, and oriental nuances. The extract phase obtained from ethanol with 50% water was found to be a promising fraction for industrial applications. Furthermore, the results proved that the NRTL parameters can be efficiently used to predict the compositions of the phases from the LLE.