Extraction Of Essential Oil Essay

2.3 Extraction of Essential Oils

Essential oils are used in various applications from perfumery, food and cosmetic industry to pharmaceuticals, thus there should be regular increase in the quality of the oil yielded.

Hydrodistillation is the most frequently used technique in industrial process to ex-tract essential oils, where 3 types are distinguished: the water distillation, direct steam distillation and the steam and water distillation. Water and steam exposure protect the plant constituents from decomposition since they expose it to lower temperatures. Distillation methods involve the evaporation and subsequent con-densation of liquids to produce, refine and concentrate essential oils.

Citrus essential oil extraction such as orange and

The fruits are washed initially and subjected to abrasive action on the skin with metallic micro-peaks to burst the cells that contain the oil. The pulp is composed of the solid phase, the aqueous phase and an im-miscible hydrophobic phase bearing the essential oil, which is centrifuged and the solid particles are eliminated while the aqueous phase is recovered. Then the es-sential oil is separated from the aqueous phase by a cold mechanical decantation mechanism. In food industry fruit juice and the essential oil are successively re-covered for different applications.

2.3.3 Dry Distillation

This process doesn’t require the use of water or steam, and is done in the ab-sence of air. This process leads to the decomposition of the woody material after heating it up and results in a residual mass, which is charcoal and a condensed liquid that separates into an aqueous phase and the tar (black viscous liquid). This method is rarely used as it has been criticized for possessing possible carcinogen-ic compounds from the tar, which lead the manufacturers to refine the oil by frac-tionated distillation to eliminate the toxic substances.

2.3.4 Other