Commercial supercritical fluid food

Selection of Components for Commercial Supercritical Fluid Food Processing Plants... 

Criteria for selection of equipment and components for commercial supercritical fluid processing plants for the food processing industry are listed and discussed. Unique features and designs for SCF food processing are specified. Requirements for vessels, heat exchangers, instrumentation, piping, fluid transport devices and typical ancillary equipment are reviewed. 

Supercritical Extraction. The use of a supercritical fluid such as carbon dioxide as extractant is growing in industrial importance, particularly in the food-related industries. The advantages of supercritical fluids (qv) as extractants include favorable solubiHty and transport properties, and the abiHty to complete an extraction rapidly at moderate temperature. Whereas most of the supercritical extraction processes are soHd—Hquid extractions, some Hquid—Hquid extractions are of commercial interest also. For example, the removal of ethanol from dilute aqueous solutions using Hquid carbon dioxide... 

Based on its ability to enhance solvating power by increasing fluid density, supercritical fluid extraction offers an attractive alternative for fractionation of fats and oils. It works by the phenomena of selective distillation and simultaneous extraction, as has been shown by many researchers [3-5]. While the use of supercritical fluids in the extraction of numerous biomaterials has been reported, its commercialization has been limited to the decaffeination of coffee and tea and to the extraction of flavors from hops and spices. The chemical complexity of most food ingredients and their tendency to react and degrade at elevated temperatures, emphasize the difficulties of supercritical solvent selection. Carbon dioxide is the preferred supercritical solvent (its properties have previously been cited [6]). 

Passey CA. Commercial feasibility of a supercritical extraction plant for making reduced-calorie peanuts. In Rizvi SSH, ed. Supercritical Fluid Processing of Food and Biomaterials. London Blackie Academic, 1994 223-243. 

In the early years, the petroleum industry acted as a catalyst for the development of this physical method. However, over the past twenty-five years, organic mass spectrometry has been the subject of a series of major developments. Some of them, such as the advent of commercially available interfaces for gas-liquid, high performance liquid, and supercritical fluid chromatographs, as well as novel ionisation techniques particularly well suited for high molecular weight, non-volatile macromolecules were welcome and well-accepted by the food analysts. Others, such as the introduction of relatively inexpensive quadrupole mass filters that proved to be reliable and... 

The term supercritical fluid is used to describe any substance above its critical temperature and pressure. The discovery of the supercritical phase is attributed to Baron Cagniard de la Tour in 1822 [3], He observed that the boundary between a gas and a liquid disappeared for certain substances when the temperature was increased in a sealed glass container. While some further work was carried out on supercritical fluids, the subject remained essentially dormant until 1964 when a patent was filed for using supercritical carbon dioxide to decaffeinate coffee. Subsequent major developments by food manufacturers have led to the commercialization of this approach in coffee production. The use of supercritical fluids in the laboratory was initially focused on their use in chromatography, particularly capillary supercritical fluid chromatography (SFC). However, it was not until the mid-1980s that the use of SFE for extraction was commercialized. 

Some of the areas in which supercritical CO2 (SCCO2) is commercially important are summarized in Figure 8.9. Extraction processes in the food, tobacco (nicotine extraction) and pharmaceutical industries dominate. Supercritical CO2 is a selective extracting agent for caffeine, and its use in the decaffeination of coffee and tea was the first commercial application of a supercritical fluid, followed by the extraction of hops in the brewing industry. Solvent extractions can be carried out by batch processes, or by a continuous process in which the CO2 is recycled as shown schematically below ... 

Major applications of SFE-SFC are somewhat limited at the moment to the analysis of lipids and pesticides from foods and similar matrices and different types of additives used in the production of polymers [79,146,188-194]. The approaches used cover a wide range of sophistication and automation from comprehensive commercial systems to simple laboratory constructed devices based on the solventless injector [172,174,175,188]. Samples usually consist of solid matrices or liquids supported on an inert carrier matrix. Aqueous solutions are often analyzed after solid-phase extraction (SPE-SFE-SFC) to minimize problems with frozen water in the interface [178,190]. The small number of contemporary applications of SFE-SFC reflects a lack of confidence in supercritical fluid chromatography as a separation technique and competition for... 

Not every pharmaceutical will eventually be comminuted by supercritical fluid nucleation, not every polymer processed for molecular weight control by supercritical fluid extraction, not every flavor concentrated by supercritical fluid extraction but some will be. Two applications listed in the table are already in commercial production, and several are in advanced pilot plant development and test market evaltiation. Hops extraction is being carried out by Pfizer, Inc. in its plant in Sydney, NE (33), and General Foods Corporation has constructed a coffee decaffeination... 

Supercritical fluid (SCFCO2) processing is of increasing commercial importance to the food industry in Europe and America. Citations of SCFCO2 extractions of botanicals are replete in the literature. 

Due to its unique characteristics, carbon dioxide is the only supercritical fluid used in food industry. Research and development in this area has been prolific since the extraction of caffeine was patented in 1964 [13], After its practical application in Germany in 1978 (by the Hag AG Corporation), commercial plants have been constructed [3,14,15] for extracting ... 

The oldest commercially used SCCO2 extraction process is the decaffeination of coffee beans. This is still the most profitable application of SCCO2, but supercritical fluids have been tested in the food industry, pharmaceutical industry, textile dyeing, impregnation, polymer synthesis and processing, dry cleaning, etc. ... 

In the food industry, commercial plants with supercritical fluids have so far only been used with supercritical CO2 as solvent. The first plant was opened in 1981 in Bremen (Germany) for decaffeination of coffee, by a process invented in the 1970s by Zosel (1973). Plants for the production of hop extract and for the decaffeination of tea are today also in operation, for example, in Germany, England, and Australia (Voeste et al., 1997). Supercritical hydrocarbons such as propane are also used, for example, for deasphalting of heavy oils or for the removal of triglycerides from fish oils. 

While research employing SFC is still in the physico-chemical and operational stages, the evolution of the technique is rapidly progressing (303-305). Commercial instruments are now available, but the application of SFC to research problems is still uncommon. One area that is particularly promising is the application of SFC for assaying compounds that are extracted industrially by supercritical fluids. For example, SFC can be used as an analytical tool to quantitate caffeine (114), the oligomer content of polymerizations (111), and fats and oils in foods or petrochemical products (316). 

Licence, R, Ke, J., Sokolova, M., Ross, S.K. and Pobakoff, M. 2003. Chemical reactions in supercritical carbon dioxide From laboratory to commercial plant. Green Chem. 5 99-104. List, G., King, J. and Dunford, N.T. 2003. Supercritical fluid extraction in food engineering, in Extraction Optimization in Food Engineering, C. Zia and G. Liadaku, eds. CRC Press, 2003. 

Commercialization of a supercritical carbon dioxide processed food product requires the successful application of five sequential steps 1) application of high pressure CO2 phase equilibria and fluid dynamics theory 2) knowledge of the botanicals structure and chemistry 3) performance of the "process design protocol" 4) preliminary process design and economic evaluation and 5) design, construction and start-up of the commercial-scale plant. Many decisions made during the early steps have large impacts on commercial plant performance capabilities and economic efficiency. The impact on commercial plant performance and economics should be factored into decisions made at every commercialization step. 

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