Application and possibilities of supercritical co2 extraction in food processing industry: an overview

Food Science and Technology International
http://fst.sagepub.com/ Application and Possibilities of Supercritical CO2 Extraction in Food Processing Industry: An Overview
M. Raventós, S. Duarte and R. Alarcón Food Science and Technology International 2002 8: 269 DOI: 10.1106/108201302029451 The online version of this article can be found at: http://fst.sagepub.com/content/8/5/269

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Application and Possibilities of Supercritical CO2 Extraction in Food Processing Industry: An Overview
´ ´ M. Raventos,* S. Duarte and R.Alarcon
Escola Universitaria d’Enginyeria Te`cnica Agrı´cola de Barcelona, Urgell 187, 08036 Barcelona, Spain
The food industry is always looking for the best separation technology to obtain natural compounds of high purity, healthy products of excellent quality with several industrial applications. The conventional extraction process for those compounds has some limitations regarding thesolvent toxicity, flammability and wastefulness. Research into energetically less costly technologies with respect to the environment is required. Supercritical fluid extraction (SFE) is a relatively new extraction process that has attracted great interest in many industries. Supercritical fluid properties are used selectively to extract specific components. This paper overviews the applications ofsupercritical fluid technology in food processing using carbon dioxide as the ideal supercritical fluid because of its non-flammable, non-toxic, non-polluting and recoverable characteristics. A summary of commercial applications and examples of recent developments illustrate the different possibilities that SFE has in industrial food processes. Key Words: supercritical CO2, extraction

PRINCIPLESOF SUPERCRITICAL FLUID EXTRACTION
Many technologies have been developed for the separation and fractionation of different food compounds in the food industry. Conventional processes such as crystallisation, filtration, distillation or precipitation are being substituted by new processes that use membranes or supercritical fluids. Supercritical fluid extraction (SFE) is a separation process wherethe substances are dissolved in a fluid which is able to modify its dissolving power under specific conditions above their critical temperature and pressure (supercritical region). The properties of a supercritical fluid are used to extract selectively a specific compound or to fractionate mixtures by changing the temperature and pressure without any phase change. A supercritical fluid is aliquid or a gas at atmospheric conditions which is operational when compressed above its critical pressure (50–250 bar) and heated above its critical temperature (20–60  C). The most important property of these fluids is the dissolving power in their supercritical region. In the phase diagram for a pure compound (Figure 1, based on a phase diagram for water) it is possible to

*To whomcorrespondence should be sent (e-mail: merce.raventos@upc.es). Received 23 November 2001; revised 10 April 2002.
Food Sci Tech Int 2002;8(5):0269–16 ß 2002 Sage Publications ISSN: 1082-0132 DOI: 10.1106/108201302029451

distinguish the three material states: solid, liquid and vapour. These are separated by a fusion curve or solid– liquid equilibrium, sublimation curve or solid–vapour equilibrium, and...