Supercritical fluid extraction of tocopherol concentrates from olive tree leaves

Olive tree leaves, a residue obtained during the harvest of olives for oil production were treated with supercritical carbon dioxide to analyze the possibility of obtaining tocopherol concentrates. Oil and tocopherol extraction rates were determined as a function of pressure (25–45 MPa), particle size (0.25–1.5 mm), solvent flow (0.5–1.5 SL/min) and temperature (313–333 K). Two optimal extraction conditions were determined, considering the maximum recovery or concentration criterion. Those conditions led to a highly valuable extract of 74.5 and 97.1% (w/w) tocopherol concentration, respectively. Results obtained were compared to hexane soxhlet extraction.