Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 15, 1996
Publication Date: N/A
Interpretive Summary: The accurate analysis of fat levels in a variety of foods has become of increasing importance due to the food labeling requirements of the recently mandated Nutritional Labeling and Education Act (NLEA). The NLEA has defined "fat", based on a precise analysis of the fatty acid content of a food item. However, fat must still be removed or extracted from the foodstuff, an operation which traditionally has required the use of flammable and toxic solvents. This publication describes an alternative procedure using high pressure gases, such as carbon dioxide, to affect the removal of fat from meat samples, i.e., ground beef. The fat extract from ground beef is first isolated by precipitation from a concentrated acid solution and then placed into a cell for extraction with high pressure carbon dioxide. The extract from the carbon dioxide is then analyzed with respect to its fatty acid content, and calculations performed to yield the various quantities of different types of fat in the meat sample. The advantage of the high pressure gas extraction process is that it gives equivalent results to those obtained via traditional solvent extraction methods without introducing hazardous chemicals into the laboratory environment. The procedure will be of potential value to regulatory agencies, such as the Food Safety & Inspection Service and FDA.
A supercritical fluid extraction (SFE) method using CO2 has been developed for the removal analysis of fat from ground beef samples for nutritional analysis. The SFE procedure was coupled with a solid phase extraction (SPE) disk for the isolation of fats from acid hydrolyzed ground beef samples prior to SFE. The meat hydrolzylate is filtered and collected on the reversed-phase SPE disk which is then subjected to SFE. The extracted fat is then transesterified to fatty acid methyl esters (FAMEs) and total, saturated, and cis-monounsaturated fat determined by gas chromatography. The SFE method was tested on two commercial extractors and the results compared to a solvent-based (ether/hexane) extraction method. No significant differences were found between the results obtained by the solvent-based and the SC-CO2 methods. The SFE method proved a suitable replacement for a traditional organic solvent extraction method, thereby eliminating the use and costs associated with solvent disposal, as well as the exposure of laboratory personnel to toxic and/or flammable solvents.