Extraction of bioactive enriched fractions from Eruca sativa leaves by supercritical CO2 technology using different co-solvents

• SCCO2 extraction from rocket salad (Eruca sativa) leaves is studied for the first time.
• Glucosinolates content of an extract obtained by supercritical technology using water as co-solvent is first reported.
• A two steps process using first water as modifier followed by a second step using ethanol as co-solvent is presented.
• Optimization of the SCCO2 operative conditions is carried out and the results are compared with Soxhlet and traditional quantification methods.
• Extraction curves are fitted by the model of broken and intact cells developed by Sovová.

Supercritical fluid extraction from freeze-dried Eruca sativa leaves is assessed with the aim of studying the feasibility to obtain bioactive enriched fractions containing different classes of valuable compounds. Total extraction yields and compositions using pure CO2 and CO2 + selected co-solvents are compared. Overall extraction curves, fitted by the model of broken and intact cells developed by Sovová, are reported and the influence of the main parameters that affect the extraction process is analysed. The extract with the highest content in glucosinolates and phenols was collected at 30 MPa and 75 °C using 8% (w/w) of water with respect to the CO2 flow rate, whereas the fraction richest in lipids was obtained using 8% (w/w) of ethanol as co-solvent at 45 °C and 30 MPa. A process including a first step with supercritical CO2 extraction using water as co-solvent followed by a second step, where a fraction rich in lipids is extracted using ethanol as co-solvent, is proposed. SCCO2 results are compared with Soxhlet and other methods that combine organic solvents with ultrasounds.

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