Supercritical CO2 extraction of oil from green coffee beans: Solubility, triacylglycerol composition, thermophysical properties and thermodynamic modelling

- The present work was focused to determine the solubility of diterpene rich green coffee oil in supercritical CO2.
- The solubility of green coffee oil increased with increasing temperature under isobaric conditions.
- The fatty acid profile of green coffee oil was used to calculate probable triacylglycerol composition using a statistical algorithm.
- Binary interaction parameters between triacylglycerols and supercritical CO2 were determined using experimental data and equation of state.

The aim of this study was to measure the experimental solubility of green coffee oil (GCO) in supercritical CO2 (scCO2). Solubility was measured by static method under temperatures from 313.15 to 353.15 K and pressures of 30 and 35 MPa. The fatty acid (FA) profile was determined by gas chromatography-mass spectrometry (GC/MS). From these results, the triacylglycerol (TAG) profile was estimated by statistical methodology based on the FA composition. The thermophysical properties of the TAGs were estimated by group contribution methods The experimentally calculated equilibrium data were correlated using the Peng-Robinson equation of state (PR-EoS) with the van der Waals mixing rule. The experimentally measured solubility ranged from 12.4 to 26 g oil/kg CO2. The results showed that solubility increased with increasing temperature under isobaric conditions. However, the effect of temperature showed different behavior at 343.15 and 353.15 K, depending on the pressures.

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