Supercritical Fluid Extraction

 

Supercritical Fluid Extraction

Supercritical fluids (SCF) were first discovered by Charles Cagniard de la Tour in 1822. The high solvation power of such fluids was first reported over a century ago [1]. An SCF is a substance that is heated and pressurized above its critical point, which represents the critical pressure and temperature conditions of the substance for its both the liquid and gas phases to have the same density and to become indistinguishable [2]. A small change in temperature and pressure can dramatically change the properties of supercritical fluids, thereby making it possible to control their physico­-chemical properties such as density and solvation power [3, 4]. SCFs can easily pass through solid materials like a gas and dissolve components as a liquid solvent.

 

The extraction process by using SCFs is called Supercritical Fluid Extraction (SFE). Besides achieving high extraction yields and quality, SFE can be operated under a wide range of conditions to selectively extract specific end products with improved functional and nutritional characteristics. Also, the combined liquid-like solvating and gas-like transportation properties of supercritical fluids make them particularly suitable for the extraction of special substances such as phytochemicals, essential oils, and aroma compounds [2, 5, 6]. It is used in various extraction processes of the walnut kernel [7], apricot kernel [8], sesame [9] oils, aromatic vinegar [6], fruits and vegetables [2]. It is also used in the decaffeination of coffee and denicotinization of tobacco [10].

 

There are several SCFs used for SFE; however, supercritical CO2 is the most preferred one due to its near ambient critical temperature, absence of residual problems, and the inexpensive, odorless, colorless, nontoxic, nonflammable, and noncorrosive nature of the solvent [10]. There is a disadvantage that it can’t be used on its own for extraction processes that might include sugars, glycosides, salts, or similar compounds because of its nonpolar characteristic. However, this disadvantage can be handled by the addition of modifiers, which improves the extraction efficiency and favors the penetration of the SCF into the matrix. The most common modifiers can be listed as ethanol, methanol, acetonitrile, acetone, and water [2].

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CONTENT: Gökçe Mavioğlu

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REFERENCES


1.     Cagniard de la Tour C. 1822. Exposé de quelques résultats obtenu par l’action combinée de la chaleur et de la compression sur certains liquides, tels que l’eau, l’alcool, l’éther sulfurique et l’essence de pétrole rectifiée. Annales de Chimie et de Physique, 21, 127–132.

2.     Singh, R., Dhanani, T., & Kumar, S. (2018). Supercritical Fluid Extraction of Bioactive Compounds from Fruits and Vegetables. In E. M. Yahia (Ed), Fruit and Vegetable Phytochemicals: Chemistry and Human Health, Volume I (2nd ed.). (pp. 749-762).

3.     Abbas, K. A., Mohamed, A., Abdulamir, A. S., & Abas, H.A. (2008). A review on supercritical fluid extraction as new analytical method. American Journal of Biochemistry and Biotechnology, 4, 345–353.

4.     Casas L, Mantell C, Rodroguez, M, Torres A, Macias FA and de la Ossa EJM. 2008. Super critical extraction of bioactive compounds from sunflower leaves with carbon dioxide and water on a pilot plant scale. Journal of Super Critical Fluids, 45, 37–42.

5.     Yousefi, M., Rahimi-Nasrabadi, M., Pourmortazavi, S. M.,  Wysokowski, M., Jesionowski, T., Ehrlich, H., & Mirsadeghi, S. (2019). Supercritical fluid extraction of essential oils. Trends in Analytical Chemistry, 118, 182-193.

6.     Lu, Z., Xu, W., Yu, N., Zhou, T., Li, G., Shi, J., & Xu, Z. (2011). Recovery of aroma compounds from Zhenjiang aromatic vinegar by supercritical fluid extraction. International Journal of Food Science and Technology, 46, 1508-1514.

7.     Salgın, S., & Salgın, U. (2006). Supercritical fluid extraction of walnut kernel oil. European Journal of Lipid Science and Technology, 108, 577-582.

8.     Özkal, S. G., Yener, M. E., Bayındırlı, L. (2005). Mass transfer modeling of apricot kernel oil extraction with supercritical carbon dioxide. Journal of Supercritical Fluids, 35(2), 119–127.

9.     Odabas, A. Z., & Balaban, M. O. (2002). Supercritical CO2 extraction of sesame oil from raw seeds. Journal of. Food Science and Technology, 39, 496–501.

10.  Attokaran, M. (2017). Supercritical Fluid Extraction. Natural Food Flavors and Colorants (2nd ed.). (pp. 35-36).