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ABSTRACT:
The supercritical fluid extraction is a separation method in which separation of chemicals, flavours from the products such as coffee, tea, hops, herbs, and spices which are mixed with supercritical fluid to form a mobile phase. In this process, the mobile phase is subjected to pressures and temperatures near or above the critical point for the purpose of enhancing the mobile phase solvating power. The process begins with CO2 in vapour form. The use of supercritical fluids, especially carbon dioxide, SFE is a simple, inexpensive, fast, effective and virtually solvent-free sample pre treatment technique. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas, liquid and supercritical fluid chromatography. In this review, we showed that a number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and collection process. Finally, SFE has been compared with conventional extraction methods in terms of selectivity, rapidity, cleanliness and possibility of manipulating the composition of the extract. The principle of supercritical fliud extraction is the optimization of the solubility of materials to be extracted (lipids, heavy metals, natural products) in supercritical CO2 and the improvement of the fractionation with respect to a particular lipid species, natural products Supercritical fluid extraction facilitates the detachment of the extract from the supercritical fluid solvent by simple expansion.
KEY WORDS: supercritical fluid extraction, carbon dioxide, separation, temperature, optimizing pressure
INTRODUCTION:
The supercritical fluid extraction (SFE) technology has advanced tremendously since its inception and is a method of choice in many food processing industries. Over the last two decades, SFE has been well received as a clean and environmentally friendly "green" processing technique and in some cases, an alternative to organic solvent-based extraction of natural products. The most recent advances of SFE applications in food science, natural products, by-product recovery, pharmaceutical and environmental sciences have been published in extensive reviews Solvent extraction (SFE) is one of the old methods of separation known and certainly dates back to Paleolithic age.
The science of solvent extraction has evolved over a long period of time and much progress has been made in the understanding of solvation and the properties...