Development of Methods for Determination of Fat and Trace Constituents in Food, with Emphasis on Supercritical Fluid Extraction

Abstract: Sample preparation is the most time-consuming step in an analysis. Traditional sample preparation techniques consume large amounts of organic solvents, are time-consuming and are difficult to automate. During the last decade some new extraction techniques have been developed for sample preparation and one of them is supercritical fluid extraction (SFE). This thesis focuses on sample preparation for food analysis with emphasis on SFE. Optimisation of the SFE methods include extraction conditions as well as collection parameter for different constituents in different food formulas including total fat content, lipid classes, fatty acid composition, fat soluble vitamins, androstenone, acetoin, 2,3-butanediol and diacetyl. After the extraction the analytes have been analysed in different ways using techniques as GC, GC-MS, gravimetry, HPLC and TLC. The developed methods have generally been validated by comparing with results obtained by conventional methods. However, for acetoin, 2,3-butanediol and diacetyl the extraction efficiency was calculated from spiked meat samples with 100% recovery for acetoin and 2,3-butanediol and 63 % for diacetyl. In the thesis five different methods (Caviezel, NIR, NMR, PFG-NMR and SFE) for determination of fat content in meat also have been compared with a Nordic standard method (SBR). From this comparison it can be concluded that, if a fast method is needed, the Caviezel or SFE methods are the best choices, and if there are not any time demand for the analyse the NMR method is the best option. From the results described in these theses it can be concluded, that SFE is a fast and environmentally friendly sample preparation technique, excellent in sample preparation for food analysis.