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Super critical Fluid Extraction Applications 463

suggested that SFE extracts up to 4 times greater γ-oryzanol (5.39
mg/g of rice bran) compared to solvent extraction.
Dunford and King (2000) studied enrichment of rice bran oil (20.5
to 32.0 MPa and 45 to 80°C) to reduce free fatty acids and minimize
the loss of phytosterols and found that low-pressure high-tempera-
ture combinations are better for reducing loss of triglycerides and
phytosterols during removal of free fatty acids from crude rice bran
oil. Badal and Walker (2002) in their rice bran lipid study with super-
critical carbon dioxide (40°C, 27.58 MPa) found that oil yield was a
function of particle size during SFE. Badal and Walker’s yield was
51.5 percent of the total ether extractable oil in 2 h from small particles
(16 to 48 mesh) compared to 41.2 percent extracted from larger parti-
cle size (>48 mesh) rice bran.

16.5 Summary and Future Trends
Supercritical fluids were discovered in the 1800s, but have only been
applied since the 1960s as a means for separations and analytical
techniques. Applications toward extraction of caffeine from coffee
and hops extraction were initial commercial products. Since then,
applications ranging from high-value oil extractions, fractionation of
pharmaceuticals, sterilization of medical equipments, explosion pre-
treatment of cellulosic and oil-based sources, production of biodiesel
with supercritical methanol, and rapid expansion of supercritical fluid
solutions (RESS) for bioactive component delivery mechanisms have
been realized. The technology takes advantage of the broad thermo-
dynamic nature of fluids to give unique process characteristics that
allow for greater functionality or versatility than many conventional
methods, thus, extending the potential operational capabilities inher-
ent to biological systems processing. With greater emphasis on reduc-
tion of toxic waste streams, environmental impacts, carbon reduction,
and use of GRAS solvents, supercritical fluids have a bright future for
many new biological system applications.

References
Akgun M., Akgun N. A., and Dincer S. 2000. Extraction and modeling of lavender
flower essential oil using supercritical carbon dioxide. Ind. Eng. Chem. Res.
39(2):473–477.
Amano, N., Shinmen, Y., Akinoto, K., Kawashima, H., Amachi, T., Shimizu, S., and
Yamada, H. 1992. Chemotaxonomic significance of fatty acid composition in
the genus Mortierella. Mycotaxon 94:257–265.
Andrich, G., Nesti, U., Venturi, F. Zinnai, A., and Fiorentini, R. 2005. Supercritical
fluid extraction of bioactive lipids from the microalga Nannochloropsis sp.
European Journal of Lipid Science and Technology 107(6):381–386.
Badal, R. and Walker, H. T. 2002. Supercritical carbon dioxide extraction of lipids
from raw and bioconverted rice bran. M.S. thesis, Louisiana State University,
Baton Rouge, LA.