The edible oil refining processes are degumming or gums conditioning/neutralization, bleaching and deodorization.
The degumming and Neutralization process removes phospholipids and fatty acids to improve its physical stability. The phospholipids can lead dark coloured oil. With this process, the fatty acids, pigments, and other particles are removed.
The next step is bleaching, which is a process of selective removal of impurities and pigments by the physical and chemical interaction. The process removes colour pigments, dirt, trace metal, and phospholipids.
The last step of vegetable oil refining is deodorization, which is a vacuum stripping process where a certain quantity of stripping steam is passes through hot oil at a very low pressure. It is mainly a physical process, but because it is carried out at a high temperature, some chemical effects may take place.
