(644e) Caffeine and Chlorogenic Acid Separation from Raw Coffee Beans Using Supercritical CO2 in Water

The aim of this work was to develop new process for extracting and separating hydrophilic and hydrophobic compounds from coffee beans using supercritical CO₂ in water. In this work, experiments and simulation of the process has been conducted. Chlorogenic acid and caffeine from coffee beans were used as model compounds of hydrophilic and hydrophobic compounds, respectively. Experiment was conducted in the semi-continuous flow extractor at various densities and ratios of coffee mass and water mass (C/W). Extracted compounds in SC-CO₂ and in water were analyzed by HPLC-PDA detector, respectively. As expected, the extracted compound in SC-CO₂ was containing 100% purity of caffeine. However, the extracted compound in water was containing caffeine and chlorogenic acid. It was due to the solubility of caffeine in water is higher than that in SC-CO₂. Recovery of caffeine in SC-CO₂ increased with increasing density and decreasing ratio of coffee mass and water mass (C/W).

In addition, this process was also simulated using model based on mass transfer balance to estimate recovery of caffeine and to describe concentration profile inside of the extractor (both in SC-CO₂ phase and water phase). Simulation was conducted using Visual Basic in Excel 2003. As in the experimental result, the recovery of caffeine in SC-CO₂ increased with the increase in density. However, the effect of C/W on the recovery of caffeine in SC-CO₂ yielded adversative result. In the simulation result, the recovery of caffeine in SC-CO₂ decreased with decreasing C/W. The result can be explained that increasing mass of water caused increasing mass transfer rate of caffeine in water, thus the increasing mass transfer resistance in SC-CO₂. Concentration profile of caffeine in SC-CO₂ phase and in water phase inside of the extractor have also been simulated.