Chemical Engineering Journal, Vol.88, No.1-3, 103-109, 2002
Quality of borage seed oil extracted by liquid and supercritical carbon dioxide
This paper describes the extraction of borage seed oil by liquid and supercritical carbon dioxide, from the point of view of both operative method and pre-treatment of raw material. The best conditions for borage seed oil extraction are obtained at 300 bar, 40 degreesC and a solvent flow rate of 1.5 l/min at STR The yields obtained are very similar to those resulting from the conventional extraction process using hexane as solvent (26.0 wt.%); however, the quality of oil extracted by supercritical fluid is higher (acidity, 11.0; unsaponifiables, 1.8). The fatty acid composition of the borage seed oil extracted by SFE is particularly rich in unsaturated fatty acids, especially the gamma-linolenic acid (21.7%). For these reasons, the borage seed oil extracted using carbon dioxide could be competitive with the conventional process, since it simplifies considerably the oil refinement stages and completely eliminates the solvent distillation stage, which are the most costly processing stages in terms of energy consumption.
Keywords:supercritical fluid;supercritical fluid extraction;carbon dioxide;borage seed oil;linolenic acid;GLA