Supercritical fluid extraction of capsaicin from peppers

Supercritical Fluid Technology utilizes the unique physico-chemical properties of solvents in numerous applications. Supercritical Fluid (SF) Technology has become an interdisciplinary field, utilized by chemical engineers, chemists, food scientists, materials scientists, agronomists, and researchers in biotechnology and environmental control. The last ten years have seen the importance in SF applications expand from commodity chemicals and synthetic fuels toward more complex, highly specialized, and more valuable substances. Substantial efforts have also been directed at gaining a better fundamental understanding of phase behavior and transport properties of SFs.

Development of the technique of separating substances using SFs commenced in the early '60s, though certain fundamental principles had already been understood for more than 80 years. Every pure component has a particular temperature and pressure that is defined as the critical point. Above this temperature and pressure, the substance exists strictly as a gas. Below the critical point, it can exist as both a liquid and a vapor. For water, the critical point is 375 C and 3226 psia pressure. SFs have density and diffusivity like a liquid and viscosity like that of a gas, thus making it an attractive solvent for extraction processes. The solvating strength and the transport properties of a SF can be conveniently varied by changing the temperature and pressure (or the density) of the fluid. Depending on the conditions and the application of interest, SFs can diffuse and penetrate rapidly into the sample matrix from which the product of interest is to be separated.