Precipitation of antioxidant fine particles from Olea europaea leaves using supercritical antisolvent process

Graphical abstract for formation of OLA FPs from Olea europaea leaves. SFE: P 100bar, T 55°C, CO2 flow rate 16g/min, co-solvent (C2H5OH) flow rate 4g/min, t 180min. SAS: P 150bar, T 50°C, CO2 flow rate 20g/min, co-solvent (C2H5OH) flow rate 2g/min, t 30min. •SAS process led to successful precipitation of spherical olive leaves fine particles.•SAS processed particles had stronger antioxidant activity than the extract.•The extract concentration is the most important key to get a successful precipitation. 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 32mg/mL), temperature (35 to 60°C), pressure (100 to 200bar), CO2 flow rate (11 to 30g/min) and solution flow rate (2 to 8mL/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.