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United States Department of Agriculture

Agricultural Research Service

Title: Sfe of Fat: Reconciliation of Gravimetric and Gc-Fame Determinations

Authors
item Eller, Fred
item King, Jerry

Submitted to: Pittsburgh Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 1999
Publication Date: N/A

Technical Abstract: The purpose of this study was to develop an accurate gravimetric fat method by comparison of gravimetric and gas chromatographic fatty acid methyl ester (GC-FAME) fat determination of supercritical CO2 (SC-CO2) extracts. Gravimetric fat determination of SC-CO2 extracts are generally quite accurate for high-fat, low moisture samples, and neat SC-CO2 gives extracts scontaining the least amount on non-fat co-extractives. However, with high moisture samples, water is often co-extracted with fat giving high gravimetric values. Water present in the collected extract can easily be removed using a vacuum over, but other non-fat materials cannot be removed in this manner. The co-extraction of water can be reduced by drying the sample prior to SFE, however, in some cases, this also decreased the amount of fat that was extracted as well. The use of a drying agent within the extraction cell can be used to retain water, but adsorption of fat on some desiccants was noted, however, anhydrous NA2SO4 gave excellent results. Because some samples contain bound fat, hydrolysis prior to extraction may be required for complete fat extraction. The incorporation of a hydrolytic treatment into the SC-CO2 extraction method may be required for food products containing bound lipids within high-starch matrices, and the use of enzymatic hydrolysis is under investigation.

Last Modified: 12/22/2014
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