Different methods of extraction of essential oil
- 1. Different methods of extraction of essential oils
- 2. Introduction • The scented oil obtained from natural sources is called Essential oil. • An essential oil may be defined as a volatile perfumery material derived from a single source of plant or animal origin, which has been separated from that source by a physical process. • There are about 1300 plants in India which are known to be aromatic plant. Out of which 65 plant species have demand in the world market. • India share the 3rd largest producer of natural essential oils next to USA and Brazil.
- 3. • Further, 4th largest economy after USA, China & Japan and second fastest growing economy. Hence there is a demand for the mass consumption items. • Essential oils from aromatic plants are low volume and of high value.They have a longer shelf life at room temp. than horticultural plants. Some of them can be grown in marginal lands through contract farming. • The world production and consumption of essential oils and perfumes are increasing very fast. • Essential oils are used in a wide variety of consumer goods such as detergents, soaps, toilet products, cosmetics, pharmaceuticals, perfumes, confectionery food products, soft drinks, distilled alcoholic beverages (hard drinks) and insecticides.
- 5. Essential oils extraction method • Classical and conventional methods:- 1.Hydro distillation (HD) • Water distillation • Water and steam distillation • Direct steam distillation 2. Solvent extraction 3. Soxhlet extraction 4. Cold pressing method
- 6. Hydro distillation(H D) • In order to isolate essential oils by hydro distillation, the aromatic plant material is packed in a still and a sufficient quantity of water is added and brought to a boil; alternatively, live steam is injected into the plant charge. • Due to the influence of hot water and steam, the essential oil is freed from the oil glands in the plant tissue.The vapor mixture of water and oil is condensed by indirect cooling with water. From the condenser, distillate flows into a separator, where oil separates automatically from the distillate water.
- 8. Types of hydro distillation • There are three types of hydro distillation for isolating essential oils from plant materials: 1. Water distillation 2. Water and steam distillation 3. Direct steam distillation
- 9. Water distillation • In this method, the material is completely immersed in water, which is boiled by applying heat by direct fire, steam jacket, closed steam jacket, closed steam coil or open steam coil.The main characteristic of this process is that there is direct contact between boiling water and plant material. • The plant material in the still must be agitated as the water boils, otherwise agglomerations of dense material will settle on the bottom and become thermally degraded. • water distillation possesses one distinct advantage, i.e. that it permits processing of finely powdered material or plant parts that, by contact with live steam, would otherwise form lumps through which the steam cannot penetrate. • The main disadvantage of water distillation is that complete extraction is not possible and is used only in cases in which the plant material by its very nature cannot be processed by water and steam distillation or by direct steam distillation.
- 11. Water and steam distillation • In water and steam distillation, the steam can be generated either in a satellite boiler or within the still, although separated from the plant material. • Like water distillation, water and steam distillation is widely used in rural areas. • Moreover, it does not require a great deal more capital expenditure than water distillation. Also, the equipment used is generally similar to that used in water distillation, but the plant material is supported above the boiling water on a perforated grid.
- 12. Advantage of water and steam distillation over water distillation • Higher oil yield. • Steam and water distillation is faster than water distillation, so it is more energy efficient. Many oils are currently produced by steam and water distillation, for example lemongrass is produced in Bhutan with a rural steam and water distillation system.
- 13. Disadvantages ofWater and Steam Distillation •Due to the low pressure of rising steam, oils of high- boiling range require a greater quantity of steam for vaporization -hence longer hours of distillation.
- 15. Direct steam distillation • As the name suggests, direct steam distillation is the process of distilling plant material with steam generated outside the still in a satellite steam generator generally referred to as a boiler. • As in water and steam distillation, the plant material is supported on a perforated grid above the steam inlet. A real advantage of satellite steam generation is that the amount of steam can be readily controlled. Because steam is generated in a satellite boiler. • The plant material is heated no higher than 100° C and, consequently, it should not undergo thermal degradation. • Steam distillation is the most widely accepted process for the production of essential oils on large scale.
- 16. Advantages of direct steam distillation • Amount of steam can be readily controlled. • No thermal decomposition of oil constituents. • Most widely accepted process for large-scale oil production, superior to the other two processes.
- 17. Disadvantage of Direct Steam Distillation • Much higher capital expenditure needed to establish this activity than for the other two processes.
- 19. Solvent extraction • This method was used to extract oil from different seeds (lemon seed, aniseed, grape seed) and also from flowers & delicate plant material that would be destroyed by hot water and steam. • It is complicated and costly procedure using ethanol and n-hexane as a solvents to draw the oils from plant material. • Solvent extraction, also known as Liquid–liquid extraction. • This is done using two liquids that don't mix, for example, water and an organic solvent
- 20. • In the Solvent-Extraction method of Essential Oils recovery, an extracting unit is loaded with perforated trays of essential oil plant material and repeatedly washed with the solvent. • Solvent extraction is used on delicate plants to produce higher amounts of essential oils at a lower cost . • The quality and quantity of extracted mixture are determined by the type of extra heat applied because of the method is limited by the compound solubility in the specific solvent used. • Although the method is relatively simple and quite efficient, it suffers from such disadvantages as long extraction time and relatively high solvent consumption.
- 21. Cold Pressing (Expression) • Expression or cold pressing, as it is also known, is only used in the production of citrus oils.The term expression refers to any physical process in which the essential oil glands in the peel are crushed or broken to release the oil. • In the past the fruit pulp was removed by hands. • The rind and pith were then soaked in warm water. • Pith of the fruit absorbed water and exerted pressure due to which it became more elastic. • It was inverted which helped to rupture the oil cells on a sponge placed next to rind. • As sponge became saturated with oil it was then squeezed to release the volatile oil which was collected in a vessel and then decanted.
- 22. Source:-timesofindia.indiatimes.com/blogs/wp- content/uploads/2016/08/16_08_2016_006_024_009 .jpg
- 23. Soxhlet extraction • This is a continuous process of extraction with a hot organic solvent. • The powdered plant material is taken in a thimble which is placed in the soxhlet extractor. • The extractor, which has a siphoning system is filled on top of a round bottom flask, a condenser is fitted at the top of the extractor. • Enough quantity of the extracting solvent is poured into the flask placed on a heating mantle. • On heating the solvent evaporates, rises to the condenser, where it condenses and drains back to the extractor holding the thimble with the plant material.
- 24. • When the extractor becomes full with hot solvent the solvent siphons down to flask along with the extracted constituents. • The recycling of the evaporated solvent is allowed to continue until the extraction is complete.
- 26. Non-traditional methods 1. Supercritical fluid extraction(SFE) 2. microwave-assisted hydro-distillation(MAHD) 3. Ultrasound-assisted extraction(UAE) 4. Solvent-free microwave extraction(SFME) 5. Microwave hydro diffusion and gravity(MHG)
- 27. Super fluid extraction(SFE) • SFE is the process of separating one component(the extractant) from another using supercritical fluid as the extracting solvent. • In practice, more than 90% of all analytical supercritical fluid extraction is performed with carbon dioxide(co2) for several practice reasons. • Co2 is the most used supercritical fluid, sometimes modified by co-solvent such as ethanol or methanol. • This extraction method produces higher yield higher diffusion coefficient and lower viscosity.
- 29. Microwave-Assisted Hydro- distillation(MAHD) • Microwave hydro-distillation has been performed using the tecnokit chen (Italy, tek-2611) microwave oven. • It is a 2450Mhz multimode microwave with a maximum delivered power of 900w. • In a typical MAHD, procedure performed at atmospheric pressure. • 100gm of plant material were heated for 30 min with addition of 300ml water. • This period was sufficient to extract all the essential oils from the sample. • Each extraction was performed at least three times.
- 31. Ultrasound-assisted extraction(UAE) • Ultrasound is probably the most simple and most versatile method for the disruption of cell and for the production of extracts. Its is efficient, safe and reliable. • Due to ultrasonic cavitation creates shear forces that breaking cell walls mechanically and improving the material transfer; this effect is being used in the extraction of liquid compounds from solid cells(solid-liquid extraction).
- 32. Source:- researchgate.net/profile/Ir_Ts_Ahmad_Ziad_Sulaiman_ Phd/publication/303804439/figure/fig2
- 33. Solvent-free microwave extraction(SFME) • This method is based on the integration of dry distillation and microwave heating energy. • It consist on the microwave dry-distillation at atmospheric pressure of plant without adding water or any organic solvent. • In a model SFME procedure, the plant material was moistened before to extraction by soaking in certain amount of water for 1-2 hr and then draining off the excess water. • After that moistened material were subjected to the microwave oven cavity and a condenser was used to collect the extracted essential oils in a presetting procedure. • the irradiation power, temperature and extraction time were controlled by the panel in the instrument.
- 34. Microwave hydro diffusion and gravity(MHG) • MHG become clear not only as economic and efficient but also as environment- friendly not require solvent or water and as it does require les energy. • The performance and advantages of this technique are a reduction of extraction time (in the case of hydro distillation it takes 90min or more but in this technique only 20 min) and reducing environmental impact and power saving.
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