The purpose of this process is the removal of materials effecting oil in terms of odour , flavour, acidity and colour.The removed materials during deodorization process can be categorized in three goup like ;
Saponifiable materials: Free oil acids, by – glycerides , methylic esters and wax – like materials.
Unsaponifiable materials: Paraffinic hydrocarbons,olefinic and polyolefinic materials, sterols and tritrphenic alcoholes
And material formed as a result of oxidative reactions:Aldehydes , ketones and peroxides.Unwanted odorants and colorants are tied to the chains of fat acids in the molecules of triglycerides with Van Der Walls force. These materials have low vapour pressure under high temperature .For that reason .İt is possible to approximate the vapour pressure of these materials to an distillable pressure under low pressure (1-8 mm) to the dragging effect of vapour gotten through the directly- injected vapour into the oil . The process of deodorization is applied under vacuum for not only to be taken advantage of vapour efficiently and be kept away of hot oil from atmospheric oxidation and its negative effects but also be prevented of free oil acids from formation .
The process of deodorization is carried out under the temperature of between 220 and 300 centrigrade degree. However , high temperature leads to the izomerization of unsaturated oil acids and as a result , the formation of isomer structure and the loss of tocopherols which distillation with vapour is applied. In addition to removal of colourant and odorant compounds , several other chemical reactions which have an influence upon stability and quality of deodorized oil is executed in deodorization process.