Solvent Supercritical Fluid Extraction Steam Distillation Process
Methods OF Oleoresin Extraction
Chilly oil and oleoresin are extracted by solvent extraction process, Supercritical fluid extraction process or steam distillation process.
Solvent Extraction Process
Oleoresins are obtained from spices by extraction with a non-aqueous solvent followed by removal of the solvent by evaporation. To start with various raw spices are cleaned and then ground to the required mesh size. Then extraction is undertaken with the help of proper solvent. Solvents that can be used are hexane, acetone, ethylene dichloride or alcohol. Extraction is done by percolation of the solvents at room temperature through a bed of ground spice packed in a SS percolator. Then the dark viscous extract containing not less than 10% of total soluble solids are drawn off and distilled under reduced pressure to remove the excess of solvent. The essential oil is obtained by steam distillation.
Therefore the capsicum or chilly oleoresin is a viscous liquid derived by polar solvent extraction from ground powder of any Capsicum species; there are three types of oleoresin: paprika (used for colour), red pepper (used for colour and pungency), and Capsicum (used for pungency).
Supercritical Fluid Extraction Process
A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. In addition, close to the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be “fine-tuned”.
The advantages of supercritical fluid extraction (compared with liquid extraction) are that it is relatively rapid because of the low viscosities and high diffusivities associated with supercritical fluids. The extraction can be selective to some extent by controlling the density of the medium and the extracted material is easily recovered by simply depressurizing, allowing the supercritical fluid to return to gas phase and evaporate leaving no or little solvent residues. Carbon dioxide is the most common supercritical solvent. The use of supercritical fluids is essentially limited to supercritical carbon dioxide (SCFCO2)extraction since carbon dioxide has the advantages of being inexpensive and nontoxic and because its critical point is easily reached.
Steam Distillation Process
Different processing methods are required to extract essential oils from different plants. Most oils are extracted using steam distillation, during which the plant material is permeated with steam. As the plant tissues break down, the essential oils and water vapor are released, then collected and cooled. The volatile essential oil condenses, separates and is easily isolated. In this process the steam is prepared in a separate chamber and piped into the tank. This is more expensive than the other methods. This is especially good for plant materials with high boiling point oils. In this method the temperature and pressure can be increased for certain oils. The rate of distillation and yield of oil are high and the quality of the oil is good.