Marigold (Calendula officinalis L.) oleoresin: Solubility in SC-CO2 and composition profile

The solubility of marigold (Calendula officinalis L.) oleoresin in supercritical CO2 (SC-CO2) and the composition profile of the extracts obtained using different extraction methods were investigated. Supercritical experiments were performed at different temperature (20–40 °C) and pressure (120–200 bar) levels. The oleoresin solubility in SC-CO2 was determined through the dynamic method using low solvent flow rates (0.79–1.67 g CO2/min), by assuming that the solvent was saturated downstream the extractor. The solubility varied from 4.74 × 10−4 to 17.04 × 10−4 g oleoresin/g CO2 and was correlated using the density-based equation proposed by Chrastil. The composition profile of the marigold oleoresins obtained with supercritical fluid extraction (SFE) and with organic solvent extraction using n-hexane, dichloromethane and butanol, were evaluated and compared. The results have shown differences in the composition profiles obtained from the marigold cultivated in Brazil (this work), compared to the ones from Europe culture (literature results).