Supercritical CO2 extraction of essential oil and oleoresin from chamomile (Chamomilla recutita [L.] Rauschert)

Flowers of chamomile (Chamomilla recutita [L] Rauschert) were extracted with supercritical carbon dioxide using a fixed bed extractor. The experimental work was conducted to identify the best process conditions to maximize the yield of extract and its content of alpha -bisabolol and chamazulene. The experimental setup used a fixed bed extractor (diameter of 3.96 x 10(-2) m and length 16.55 x 10(-2) m). The fixed bed was formed with triturated chamomile ( - 28 to + 200 mesh) with an apparent density of 370 kg/m(3). Assays were conducted at temperatures of 30 and 40 degreesC, pressures of 100, 120, 160 and 200 bar. The solvent flow rates were 1.67 x 10(-5), 3.33 x 10(-5) and 6.67 x 10(-5) kg/s. A typical run took 10 h. The chemical composition of the extracts was determined using GC/MS and GC. The pressure and solvent flow rate significantly affected the mass transfer rate and the yield while the temperature did not. The maximum yield (mass of extract/mass of dried feed) was 4.33% (40 degreesC, 200 bar, 6.67 x 10(-5) kg/s). The overall extraction curves were well described by both a spline fitting and the pseudo steady state model of Sovova. The major compounds of the essential oil and of the oleoresin were beta -farnesene, alpha -farnesene, gamma -cadinene, alpha -bisabolol oxide B, alpha -bisabolol, chamazulene, alpha -bisabolol oxide A, cis and trans-dicycloether (MW 200). (C) 2001 Elsevier Science B.V. All rights reserved.