ESSENTIAL OIL EXTRACTION BY USING CO2 SUPER CRITICAL PROCESS AND STEAM DISTILLATION PROCESS

Essential oil also called etheral or volatile oils are volatile odoriferous bodies of an oily character derived mostly form vegetable sources. They occur in small concentrations in special cells, glands or ducts, either in one particular organ of the plant or distributed over many part e.g. Leaves, barks, roots, flowers or fruits. Occasionally, they are present in combination with sugars, as glycosides, e.g. amyodalin in bitter almonds and sinigrin in mustard seeds, and are liberated when the glycosides are hydrolyzed. Essential oils are insoluble in water, but freely soluble in alcohol, either, fatty oils and mineral oils. They are commonly liquid at ordinary temperature and some of them deposit solid matters on standing most of the essential oils are optically active, are lighter than water and possess high refractive index. They are composed of a number of chemical compounds:- Hydrocarbons, Alcohols, Ethers, Aldehydes Ketones, Oxides and lactones etc. M. Indica is found largely in the greater part of India upto an altitude of 1200 M. Its bark is dark colour and cracked. Its leaves are clustered near the ouds of the branches. It is coriaceous, pubescent when young almost glabrous when mature the flowers of this tree are dense fasciles near ends of branches. They may be small, calyx, corolla tubular and fleshy. M. Indica is found in mixed deciduous forests, usually of a somewhat dry type, often growing on rocky and sandy soil and turning on the deccan trap. It is common throughout central India, Mumbai and Andhra Pradesh. It is also common in the drier type of sal forests in Madhya Pradesh. It is much planted in the plains of northern India and Deccon peninsula when forest land is cleared for cultivation, mahua trees are carefully preserved. Products derived from plants in which the odoriferous characteristics are concentrated. Essential oils are also known as “Volatile” and “etheral” oils, in contradistinction to the fixed or glyceride vegetable and animal oils and the mineral oils. Essential oils have been obtained from about eighty-seven plant families, and at times different essential oils can be secured from different parts of the same plant. For instance, the flowers of the orange tree yield oil of neroli, or oil of orange flowers; the rind yields orange oil, and another essential oil is obtained from the leaves. Classification. The essential oil can be classified in several ways. According to use, essential oils are divided into three broad classes: (1) those used for perfumery, soap, and cosmetics; (2) those used for flavouring foods and beverages; and (3) those used for therapeutic purposes. According to preparation there are five principal groups of essential oils namely, oils obtained (1) by expression, (2) by distillation, (3) by solvent extraction, (4) by counter current extraction, and (5) by enfleurage. According to sources, essential oils are classified by the eighty-seven plant families mentioned above and also by the various parts of the plant which are utilized (e.g. Fruits, seeds, bud and flowers leave and stem roots, bark, or wood). Classification according to geographical origin is also common since superior types of essential oils are produced in specific geographical areas that have favourable soil and climatic conditions. Properties. Essential oils are generally colorless to slightly yellowish when freshly distilled but when foreign matter is present, the color may range from red to blue. On standing the oils generally become darker in color. The odor of essential oils is similar to that of the portion of the plant from which they are derived; but since these odorous characteristics are much more concentrated in the essential oil, the odor is often disagreeable. The terpenes they contain are fairly readily oxidized, resulting in a turpentine odor. The specific gravity of these materials varies from 0.84 to 1.18. They are volatile at room temperature and evaporate completely when heated. Most essential oils are only slightly soluble in water; they are more soluble in sugar solutions. The principal terpeneless oils and sesquiterpeneless oils are bergamot, grapefruit, lavender, lemon, lime mandarin, orange, orrisroot, peppermint, petitgrain, and spearmint.