The supercritical fluid extraction and chromatographic analysis of fatty acids in blue cheese
Mohyuddin, Ghulam
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https://hdl.handle.net/2142/19000
Description
Title
The supercritical fluid extraction and chromatographic analysis of fatty acids in blue cheese
Author(s)
Mohyuddin, Ghulam
Issue Date
1993
Doctoral Committee Chair(s)
Artz, William E.
Department of Study
Food Science and Human Nutrition
Discipline
Food Science
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture
Technology
Food Science
Language
eng
Abstract
"The piquant and peppery flavor of American Blue and Roquefort cheese is largely due to the short and medium chain fatty acids, methyl ketones and secondary alcohols. The free fatty acids contribute flavor themselves and are also precursors of methyl ketones. Lipase action during the cheese ripening leads to formation of free fatty acids (FFA). The short chain FFA (C6 to C10) are more peppery in flavor than long chain FFA. Conventional methods of FFA analysis suffer from limitations such as loss of volatile fatty acids during derivatization of samples and difficulties in extraction and separation of short, medium and long chain fatty acids in a single analysis. Enhanced FFA recoveries from spiked matrix samples were obtained at 680 atm by SFE/SFC procedure with a 5% methanol modifier containing 1% acetic acid. A procedure was developed utilizing supercritical fluid extraction to isolate the FFA and subsequently separate and quantitate the FFA with supercritical fluid chromatography. The extraction with supercritical CO$\sb2$ and a modifier of 5% methanol containing 1% acetic acid was done at 680 atm using a SFX 2-10 Isco Supercritical Fluid Extractor (Model 100DX, Lincoln, NE). The supercritical fluid chromatographic separations were conducted by a Lee Scientific SFC, Model $\beta$501 (Salt Lake City, UT) and a capillary column (17 m x 50 $\mu$m i.d.) with a stationary phase of 25% cyano propyl polymethyl siloxane at 80$\sp\prime$C. The Roquefort cheese samples contained more of the fatty acids in greater amounts than the Blue cheese. No caproic and caprylic acids were detected in the American Blue cheese samples. The levels of capric and lauric acids were lower in the Blue cheese. All of these fatty acids are important for a product to have the ""peppery"" flavor popular among the consumers. Hence, a concerted effort is needed to alter the free fatty acid profile of the American Blue cheese so that it is closer to that of Roquefort cheese."
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