A Search for Optimum Extraction Conditions of Flavor from Tobacco Leaves by High Pressure Carbon Dioxide

To determine the optimum operating conditions for extraction of high quality flavor from tobacco leaves with high pressure CO₂, we systematized experimentally the relation between the operating conditions and flavor quality by semi-batch extractions with liquid and/or supercritical CO₂ solvent. Firstly, a general classification method of flavor components was proposed, in which the flavor components were grouped into three components based on chemical characteristics, that is a water-soluble flavor, an essential oil, and nonvolatile flavor components. Then, this method was applied to the tobacco flavor and three principal flavor compounds were selected from each component; nicotine from the water-soluble flavor component, neophytadiene from the essential oil component, and solanesol from the nonvolatile flavor component. We investigated the relation between the operating mode and condition and the composition of the principal components and/or flavor quality. It was found that the composition of the principal compounds can be varied widely by the operating conditions. Based on this result, an operating map was constructed which represents a relation between the operating condition and the composition of the principal compounds. Furthermore, the composition of the principal components of the high quality tobacco flavor determined by sensory evaluation tests was found exist in a specified area in the triangular diagram of the three principal components. This triangular diagram was a composition map which relates between the composition of the principal compounds and the quality of tobacco flavor. The optimum operating conditions for tobacco flavor having an objective quality can be determined systematically by matching the operating map and the composition map.