A supercritical antisolvent (SAS) process was carried out to obtain precipitates with potent antioxidant activity. An extract obtained by supercritical fluid extraction (SFE) of olive leaves was used in this study. The effects of different parameters on the outcome of the SAS process were analyzed: concentration (16 and 32 mg/mL), temperature (35 to 60 degrees C), pressure (100 to 200 bar), CO2 flow rate (11 to 30 g/min) and solution flow rate (2 to 8 mL/min). The antioxidant activities of both the extract and the fine particles were evaluated by the DPPH assay. The antioxidant activities were much higher for the fine particles obtained by SAS precipitation than for the extracts obtained from olive leaves by SFE. (C) 2014 Elsevier B.V. All rights reserved.