The purpose and method of edible oil refining

Crude oils & fats that are obtained after mechanical expelling or solvent extraction process contain several unwanted items in them, which needs to be refined for making it conducive for edible intake. An edible oil refinery removes these unwanted constituents and it can refine almost all types of oils.

The purpose of oil refining

Oil refining usually refers to the purification of unrefined oil to make it reach the edible or industrial oil standard. Though most of the unrefined oil is fat, it contains some impurities that not only affect the edible value and storage, but also bring difficulties to the deep processing. However, the purpose of refining is not to remove all the impurities of oil. Impurities that are harmful to the consumption, storage and industrial production would be removed, such as gossypol, protein, phospholipids, mucus and water. While the beneficial “impurities” like tocopherol would be reserved. Therefore, the purpose of oil refining is to remove the undesired and harmful impurities from the oil according to different requirements and purposes to get the oil products that can meet certain quality standards.

Method for oil refining

According to the operating characteristics and the selection of raw materials, the method of oil refining can be roughly divided into three types: mechanical method, chemical method and physical method.
The refining methods mentioned above generally can not be completely separated. Sometimes, one refining method could produce another refining effect. For example, alkali refining (neutralize free fatty acids) is a typical chemical method. However, the niger produced in neutralization reaction can absorb part of the pigment, mucus and protein, and separated together from the oil. Thus, alkali refining is accompanied by physical and chemical processes.

Oil refining is a complex and flexible work. Appropriate method of edible oil refining should be used according to the purpose of oil refining and considering both technical conditions and economic benefits.