Essential Oils: From Conventional to Green Extraction

As previously described, EOs are defined as products extracted from natural plants by physical means only such as distillation, cold press and dry distillation. However, the loss of some components and the degradation of some unsaturated compounds by thermal effects or by hydrolysis can be generated by these conventional extraction techniques. These disadvantages have attracted the recent research attention and stimulated the intensification, optimization and improvement of existing and novel “green” extraction techniques. All these techniques are appropriately applied with a careful consideration of plant organs and the quality of final products. Moreover, the analytical composition of EOs extracted from the same plant organ may be quite different with respect to the techniques used. These conventional extraction techniques could typically extract EOs from plants ranging from 0.005 to 10 %, which are influenced by the distillation duration, the temperature, the operating pressure, and most importantly, the type and quality of raw plant materials.