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United States Department of Agriculture

Agricultural Research Service

Title: Supercritical Co2 Extraction of Fat: a Comparison of Gravimetric and Gc-Fame Methods

Authors
item ELLER, FRED
item King, Jerry

Submitted to: Supercritical Fluids International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 1998
Publication Date: N/A

Technical Abstract: For close to a century, gravimetric determination of the fat content of food has been the mainstay of food and related industries. With the development of the Nutrition Labeling & Education Act (NLEA), the definition and analytical determination of fat content in food changed, requiring that a more elaborate assay be conducted for fat content, that included preextraction hydrolysis of the sample followed by gas chromatographic determination of the constituent fatty acids comprising the extracted fat. In this study, we employed supercritical fluid extraction (SFE) using supercritical carbon dioxide (SCCO2)/cosolvent mixtures and determined the fat content of oilseed, meat, and bakery samples by both gravimetric and the NLEA advocated procedure. For many of the sample matrices investigated, there was a statistically verified difference between the results from gravimetry and from the NLEA procedure. In selected cases, the two methods were equivalent, lending some credence that gravimetric based assay of SCCO2 derived extracts can be used with confidence to estimate fat levels in food products. Similar studies, comparing the results using an organic solvent based procedure with those using SCCO2 followed by gas chromatographic analysis of the fatty acid content, showed the two methods to be equivalent. This result suggests that the chromatographic based method consistently yields a more accurate evaluation of the fat content in the above sample types. These studies also serve as a guideline for correcting gravimetric derived fat values to those substantiated by NLEA analysis for specific food products.

Last Modified: 7/28/2014
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