| Summary: | The principal objective of this study was to extract
sunflower (Helianthus annuus) oil from seed with
supercritical carbon dioxide (sc-C02) as an alternative to
the cold-press method and subsequent 3-stage refining of
the acquired crude oil.
Extractions were performed on laboratory scale with a
commercially available supercritical fluid extractor of
the latest design.
A minimum number of extraction runs based on a
statistical design was performed to establish the
conditions (time, pressure, temperature) required for a
maximum yield of oil by virtue of surface response
analysis and kinetic yield-versus-time data fitting.
Several additional extraction runs were performed at
randomly selected conditions to properly reveal the
temperature, pressure and density dependence of the
extraction process and thereby elucidate its mechanism.
The physical appearance, chemical quality and composition
of the sc-C02 derived sunflower oil were evaluated against
the crude and refined oil obtained by the cold-press
method as well as a standard specification for commercial
sunflower oil. This evaluation was done by chemical
analysis performed in the quality control laboratory of a
commercial sunflower oil supplier and by GC and GC-MS
analysis of samples of both sc-C02 and cold-press obtained
sunflower oil. It was concluded that sunflower oil of a
superior quality can be obtained by sc-CO2 extraction,
especially when de-hulled seed is used to minimise the
wax content of the extract.
Extraction runs were performed on seed with natural
moisture content as well as on oven-dried, freeze-dried
and sun-dried seed in order to establish the crucial role
played by moisture content as a yield-determining factor.
Preliminary results of up scaling on a supercritical
pilot-plant suggest that sc-C02 extraction of sunflower
oil could be performed on industrial scale should an
extruder based continuous feed mechanism and a viable
process of de-hulling of seed be implemented. === Thesis (M.Sc. (Pharmaceutical Chemistry))--North-West University, Potchefstroom Campus, 2005.
|
|---|
