Guava (Psidium guajava L.) seed oil obtained with a homemade supercritical fluid extraction system using supercritical CO2 and co-solvent

In this work we designed and built a homemade supercritical fluid extraction (HM-SFE) system, in which pure CO₂ and CO₂ with co-solvents were used. The HM-SFE was made by means of thermal dilatation-contraction (TDC). This HM-SFE system was used for obtaining guava (Psidium guajava L.) seed oil, using supercritical CO₂ adding ethanol as co-solvent (CO₂ SC/EtOH), extractions were performed at 313 K and different pressures (10, 20 and 30 MPa), each one in four stages of 30 min, the extract with higher yield was subjected to transesterification and high-resolution gas chromatography (HRGC) analysis. The highest extraction yield was obtained at 30 MPa (17.30% w/w), this yield was higher than one observed in a previous work using SC-CO₂, and near to the one obtained by Soxhlet extraction (20.2% w/w). HRGC enabled the identification of components of the derivatized extract as methyl esters of palmitic, oleic, linoleic, and stearic fatty acids. The results obtained with HM-SFE system was compared with a commercial SFE system, obtained very similar results. In this work was possible to construct a low cost and simple manner HM-SFE system which was employed for obtaining guava seed oil, using CO₂ SC/EtOH.