Journal of Supercritical Fluids, Vol.133, 49-57, 2018
High pressure phase equilibrium of the crude green coffee oil - CO2 - ethanol system and the oil bioactive compounds
Green coffee oil (GCO) is highlighted for applications in cosmetics industry, however GCO is usually obtained by cold pressing. In order to develop its extraction by supercritical technology experimental equilibrium data are required. This work presents phase equilibrium data of systems containing GCO, supercritical carbon dioxide (scCO(2)) and ethanol, and evaluates the content of free fatty acids (FFA) and diterpenes in the samples. GCO solubility was evaluated at different temperatures (40-60 degrees C), pressures (200-400 bar) and scCO(2)/ethanol ratios (0-5.7% w/w of ethanol). GCO solubility in scCO(2) was similar to other vegetable oils and Chrastil semi-empirical model fit well to the experimental data. By using 2.9% ethanol, the GCO solubility increased 63%. The samples presented FFA, kahweol and cafestol contents up to 3.4, 4.4 and 4.0 times higher than commercial GCO, respectively. The use of scCO(2) with or without ethanol promotes the extraction of GCO with higher FFA and diterpene contents.