title: Optimization of a supercritical fluid extraction/reaction methodology for the analysis of castor oil using experimental design.
abstract: The aim of this work was to optimize a supercritical fluid extraction (SFE)/enzymatic reaction process for the determination of the fatty acid composition of castor seeds. A lipase from Candida antarctica (Novozyme 435) was used to catalyze the methanolysis reaction in supercritical carbon dioxide (SC-CO(2)). A Box-Behnken statistical design was used to evaluate effects of various values of pressure (200-400 bar), temperature (40-80 degrees C), methanol concentration (1-5 vol %), and water concentration (0.02-0.18 vol %) on the yield of methylated castor oil. Response surfaces were plotted, and these together with results from some additional experiments produced optimal extraction/reaction conditions for SC-CO(2) at 300 bar and 80 degrees C, with 7 vol % methanol and 0.02 vol % water. These conditions were used for the determination of the castor oil content expressed as fatty acid methyl esters (FAMEs) in castor seeds. The results obtained were similar to those obtained using conventional methodology based on solvent extraction followed by chemical transmethylation. It was concluded that the methodology developed could be used for the determination of castor oil content as well as composition of individual FAMEs in castor seeds.
authors.affiliation: Western Regional Research Center, US Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA.
authors.forename: Charlotta
authors.initials: C
authors.lastname: Turner
authors.forename: Linda C
authors.initials: LC
authors.lastname: Whitehand
authors.forename: Tasha
authors.initials: T
authors.lastname: Nguyen
authors.forename: Thomas
authors.initials: T
authors.lastname: McKeon
mesh_terms: D002367:Ricinus communis / Q000737:chemistry*; D002368:Castor Oil / Q000032:analysis*; D025924:Chromatography, Supercritical Fluid; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D005656:Fungal Proteins; D008049:Lipase / Q000378:metabolism; D000432:Methanol; D008745:Methylation; D012639:Seeds / Q000737:chemistry*
chemical_list: D004952:Esters; D005227:Fatty Acids; D005656:Fungal Proteins; D002368:Castor Oil; D008049:Lipase; C431349:lipase B, Candida antarctica; D000432:Methanol