Products extracted, using supercritical

Table3.3.11 Examples of products extracted using supercritical CO 2. Data from Goedecke (2005).

Mukhopadhyay, Natural Extracts Using Supercritical Carbon Dioxide, CRC Press, Boca Raton, Fla., 2000 Moyler, Extraction of flavours and fragrances with compressed CO2, in Extraction of Natural Products Using Near-Critical Solvents, King and Bott (eds.), Blackie Academic Professional, London, 1993. 

The flavors and fragrances extracted using supercritical carbon dioxide are signiflcantly different from those extracted using steam distillation or solvent extraction. The SFE extract can almost be viewed as a new product, as usually the amount extracted is higher (Table 2) and the composition of the extract is somewhat different (Table 3), as more aromatic molecules... 

Leitner reported that lower densities of SCCO2 can be used to extract product from a reaction mixture without coextraction of a homogeneous catalyst. This process, which he called CESS (catalysis and extraction using supercritical solution), was demonstrated with styrene hydroformylation [Eq. (23), ligand L ] and imine hydrogenation [Eq. (22)]. The catalyst was used for three cycles before drops in the conversion and selectivity was observed (101,111,133). Sellin and Cole-Hamilton used catalysts specifically chosen for their insolubility in SCCO2 to facilitate the catalyst/product separation in a CESS process (134). 

When ionic liquids are used as replacements for organic solvents in processes with nonvolatile products, downstream processing may become complicated. This may apply to many biotransformations in which the better selectivity of the biocatalyst is used to transform more complex molecules. In such cases, product isolation can be achieved by, for example, extraction with supercritical CO2 [50]. Recently, membrane processes such as pervaporation and nanofiltration have been used. The use of pervaporation for less volatile compounds such as phenylethanol has been reported by Crespo and co-workers [51]. We have developed a separation process based on nanofiltration [52, 53] which is especially well suited for isolation of nonvolatile compounds such as carbohydrates or charged compounds. It may also be used for easy recovery and/or purification of ionic liquids. 

This chapter reviews recent findings about the health benefits of phytochemicals present in fruits, vegetables, nuts, seeds, and herbs, including phenolics, carotenoids, sterols, and alkaloids. These phytochemicals are extracted using emerging technologies such as supercritical carbon dioxide (SC-CO2) extraction, PEF, MWE, HPP, UE, and OH. The impact of important parameters related to sample preparation (particle size and moisture content) and extraction process (temperature, pressure, solvent flow rate, extraction time, and the use of a cosolvent) on the efficiency of extraction and on the characteristics of the extracted products is evaluated based on an extensive review of recent literature. The future of extraction of phytochemicals is certainly bright with the... 

Lack A and Seidlitz H. 1993. Commercial scale decaffeination of coffee and tea using supercritical CCb. In King MB and Bott TR, editors. Extraction of natural products using near-critical solvents. Glasgow Blackie Academic, p. 101—139. 

The resinoids described above should be distinguished from prepared oleoresins (e.g., pepper, ginger, and vanilla oleoresins), which are concentrates prepared from spices by solvent extraction. The solvent that is used depends on the spice currently, these products are often obtained by extraction with supercritical carbon dioxide [223a]. Pepper and ginger oleoresins contain not only volatile aroma compounds, but also substances responsible for pungency. 

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