Supercritical Fluid Extraction (SFE) Techniques as an Innovative Green Technologies for the Effective Extraction of the Active Phytopharmaceuticals

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.