Perilla frutescens leaves is valuable as a medicinal plant as well as a natural medicine and functional food. Perilla leaves are an important source of essential oils and had antidepressive, anxiolytic, chemopreventive and strong antitumor-promoting activities.
Four different isolation techniques, specifically ultrasound-assisted supercritical carbon dioxide (USC-CO2) extraction, heat-reflux extraction (HRE), conventional supercritical carbon dioxide (SC-CO2) extraction and hydrodistillation (HD) were employed to obtain essential oils from purple-leafed of Perilla frutescens. The essential oils were further analyzed using gas chromatography (GC) with flame ionization detection and gas chromatography with mass spectrometry (GC-MS). Results: The maximum yield of oil was extracted via USC-CO2 extraction (1.62%, weight of the extracted oil/weight of feeding material) while utilizing less severe operating parameters, such as temperature (49 °C), pressure (28 MPa), organic solvent (0 mL) and the time consumed (105 min) by the process. The results revealed that the dominant component was perillaldehyde (> 40%) in total average content.
To evaluate the feasibility of supercritical separation processes and for establishing optimum operation conditions, a second-order kinetic model and a mass transfer model based on Fick’s law were applied to appraise the kinetics and thermodynamics aspects of perilla oil extraction employing the USC-CO2 systems. Additionally, the thermodynamic properties of essential oil in the supercritical fluid system were estimated following the theory developed by the second-order kinetic model and a mass transfer models.