Supercritical CO2 Extraction of Fat:  Comparison of Gravimetric and GC−FAME Methods

This study compares gravimetric and gas chromatographic (GC) fatty acid methyl ester (FAME) fat determinations of supercritical fluid extracts (SFE) from oilseeds, ground beef, bakery samples, and NIST Standard Reference Material 1544 (SRM-1544). SFE−GC−FAME and acid hydrolysis/solvent extraction (AH)/GC−FAME fat determinations are also compared. After extraction with supercritical CO2 and ethanol, the collected material was weighed and total fat determined gravimetrically (SFE−GRAV). Subsequently, an internal standard was added and the material converted to FAMEs and analyzed by GC (SFE−GC−FAME). For sunflower and cottonseed, the SFE−GRAV results were higher than the SFE−GC−FAME results, whereas the two methods were equivalent for soybeans, canola, and safflower. For the ground beef samples, SRM-1544, and the emulsified “low-fat” bakery products, the SFE−GRAV results were significantly higher than both GC−FAME results (i.e, SFE and AH). For the “high-fat” bakery samples containing shortening, the SFE−GRAV, and GC−FAME results (i.e, SFE and AH) were in good agreement. Keywords: Supercritical fluid extraction; fat analysis; gas chromatography; fatty acid methyl ester; gravimetric