Supercritical carbon dioxide extraction of turmeric oil from Curcuma longa Linn and purification of turmerones

This study investigates separation and purification of three turmerones from the turmeric oil extracted by supercritical carbon dioxide. Nearly, 800 g of supercritical carbon dioxide extraction of 75 g of 0.42 mm turmeric powders at 333 K and 300 bar obtained 6.98 wt% turmeric oil within 2.5 h. A response-surface methodology is adopted for optimizing supercritical carbon dioxide extraction to disclose that the combination of 320 K and 26 MPa gives an optimum production of turmeric oil containing 71 wt% purity of three turmerones. Subsequently, a normal phase silica gel 60 column is employed to separate and purify three major turmerones from the turmeric oil extracted by supercritical carbon dioxide. The 86 wt% purity of Ar-turmerone and 81 wt% purity of alpha+beta-turmerone have been separated, collected, and identified by liquid-solid chromatography, NMR qualification, and HPLC quantification, respectively. (C) 2005 Published by Elsevier B.V.