| Summary: | The feasibility of extracting botanical substances from samples of Cameamelum nobile
(Roman chamomile) with supercritical carbon dioxide (sc-C02) was investigated. The
advantages of clean technology and the relevance of chamomile extracts to the fragrance,
flavour, food, cosmetic and pharmaceutical industries sewed as motivation for the
investigation.
Extractions were performed on selected dried plant material using a commercial
laboratory-size supercritical fluid extractor. The extraction conditions (temperature,
pressure, time) were optimised in terms of yield of extract using computer-assisted surface
response analysis based on a statistical design. A maximum yield of 3 % (m/m) was
obtained at optimum conditions (39 ºC, 171 atm), in good agreement with steam
distillation derived yields of 0.5 - 2 % (m/m) reported in the literature.
The dependence of yield of extract on the density of the fluid allowed conclusions to be
drawn on the mechanism of extraction, and these could be supported by calculated values
of a few activation parameters. It turned out that components are either desorbed from the
plant matrix by sc-CO2 at gas-like densities or dissolved in sc-CO2 at liquid-like densities.
The extracts were analysed by GC/FID, GC/MS and GC-GC/TOF-MS. The three
chromatographic techniques were complementary in identifying the major compounds
present in the extracts, but the total of 462 substances identified by two-dimensional GC
by far exceeded the identification output of the two other techniques. The results
confirmed the acquisition of component-rich extracts with sc-CO2 with many components
also found in steam distillation extracts.
The study proved that sc-CO2 extraction has advantages over steam distillation in terms of
shorter extraction times, milder extraction temperatures and a wealth of components that
may constitute different compositions by manipulating extraction conditions. === Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2005.
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