Extraction of volatile oil from Croton zehntneri Pax et Hoff with pressurized CO2: solubility, composition and kinetics

Croton zehntneri Pax et Hoff is indigenous to the Northeastern of Brazil; is rich in (E)-anethole and is largely used in cooking to impart flavor to a variety of foods; is used in folk medicine to treat indigestion, insomnia, etc. In this work the volatile oil from C. zehntneri was extracted using pressurized CO2. Both kinetic and solubility experiments were performed at pressures of 66.7 and 78.5 bar and temperatures from 10 to 28 °C. The composition of the volatile oil was determined using gas chromatography. The maximum solubility (2.83 × 10−2 kg/kg) was observed at 15 ° and 66.7 bar while the maximum global yield (3.4%, mass) was detected at 20 °C at the same pressure. The volatile oil was formed predominantly by (E)-anethole (73.6%, area), alpha-muurolene (7.51%), methyl chavicol or estragole (2.52%), germacrene D (2.11%) and small amounts of other terpenoidic compounds. The overall extraction curves were fitted by several models from the literature. The models that best described the overall extraction curves were the Goto et al., Martínez et al., and Sovová.