Extraction of cardamom oil by supercritical carbon dioxide and sub-critical propane

Abstract

Supercritical CO 2 and sub-critical propane extraction conditions on quality attributes of cardamom oil were studied. The yield and solvent extractability were examined as a function of extraction conditions such as temperature, pressure and solvent/solid ratio. Of the quality components of the recovered oil, pigments (chlorophylls and carotenoids), volatile constituents, fatty acids and tocopherols, were determined by high-performance liquid chromatography (HPLC) and gas chromatography–mass spectroscopy (GC–MS). Cardamom was found easy-to-extract by fluid CO 2 even at sub-critical conditions with very cost-effective ratio of solvent/solid. However, the maximum level of natural pigments and antioxidants achieved was found in extracts recovered by supercritical fluid CO 2 and sub-critical propane. Addition of ethanol to CO 2 up to 25% did not improve the extractability of fatty acids, but had negative effect on aroma profile and positively affected the natural pigment of the extract. Propane was found to be more capable than CO 2 to recover seed oil at sub-critical conditions with lower ratio of solvent/solid and better quality attributes. Supercritical fluid extraction conditions affected to some extent fatty acid composition and content of volatiles in the recovered extracts.