Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 2003
Publication Date: January 1, 2004
Citation: Turner, C., Whitehand, L.C., Nguyen, T.T., Mckeon, T.A. 2004. Optimization of a supercritical fluid extraction/reaction methodology for the analysis of castor oil using experimental design. Journal of Agriculture and Food Chemistry.2004. 52: 26-32 Interpretive Summary: The goal of our research is to develop a safe domestic source of castor oil, which contains a high proportion of a hydroxy fatty. As part of this research, we need sound analytical methods to determine the hydroxy fatty acid content. This manuscript describes a statistically designed approach to develop the best experimental conditions for carrying out this analysis. By using enzymes in supercritical carbon dioxide, it minimizes the use of volatile solvents, and lends itself to automation. The method resulting from this research will allow us to process numerous samples in our goal of improving conversion of vegetable oils to oils containing hydroxy fatty acids. These have many industrial applications and will provide a useful resource for producing bio-based products, such as plastics and coatings.
Technical Abstract: The aim of this work was to optimize a supercritical fluid extraction (SFE) /enzymatic reaction process for the determination of fatty acid composition of castor seeds. Lipases from Rhizomucor miehei (Lipozyme RM-IM) and Candida antarctica (Novozyme 435) were used to catalyze the methanolysis reaction in supercritical carbon dioxide (SC-CO2). A Box-Behnken design was used to evaluate effects of varying values of pressure (200 to 400 bar), temperature (40 to 80°C), methanol concentration (1 to 5%) and water level (0.02 to 0.18%) on the yield of castor oil. Response surfaces were plotted, and these together with results from some additional experiments, gave the optimal extraction/reaction conditions. Novozyme 435 was clearly the best catalyst, and the optimal conditions included the use of SC-CO2 at 300 bar and 80°C with 7% methanol and 0.02% water. These conditions were used for the determination of oil content expressed as FAMEs in castor seeds. The results were similar to those obtained using conventional methodology. It was concluded that the developed methodology could be used for the determination of oil content as well as composition of individual FAMEs in castor seeds.