Characterization and Functional Properties of Macela (Achyrocline satureioides) Extracts Obtained by Supercritical Fluid Extraction Using Mixtures of CO₂ Plus Ethanol

Samples of approximately 30 g of dried and comminuted flowers of Achyrocline satureioides, a species popularly known as macela, were subjected to supercritical fluid extraction (SFE) using CO₂ with ethanol as a modifier or co-solvent (20% v/v). The effects of variations in the pressure (10, 20, or 30 MPa) and temperature (303 or 318 K) on the SFE performance were evaluated. The functional properties of the extracts were assessed by measuring the antioxidant activities and the concentrations of total phenolic compounds and analysis of total flavonoids. The influences of the operational parameters temperature and pressure on these properties were also evaluated. The results indicated that the temperature influence was significant for both the process performance and the functional properties. However, pressure did not appear to exert a great influence over the results obtained at 303 K.