Kinetic study of the supercritical CO2 extraction of different plants from Lamiaceae family

The supercritical CO2 extraction of four different plants from Lamiaceae family, namely oregano (Origanum vulgare), thyme (Thymus zygis), sage (Salvia officinalis) and rosemary (Rosmarinus officinalis) was carried out in an experimental pilot-plant comprising an extraction cell of 2 L capacity. 600 g of leaves of each plant material, with the same pre-treatment, were extracted at the same pressure and temperature (30 MPa and 313 K) and using 2.4 kg/h of CO2. Further, the same fractionation procedure in a two on-line decompressing separators at, respectively, 10 MPa and 0.1 MPa was employed. In this way, a thoughtful comparison of the extraction kinetic was established and discussed, in terms of the extraction yields attained in the separators, the variation of the essential oil composition with time and the content of key bioactive substances identified in the different fractions.

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► SFE kintics of thyme and rosemary are much faster than salvia and oregano.
► Oregano extract is mainly recovered in the first separator.
► Sage and thyme extracts are mainly recovered in the second separator.
► Similar amounts of rosemary extract were recovered in both separators.
► SFE of terpenes decrease while SFE of diterpenes increase with extraction time.