#physical refining process

• The process of physical refining involves degumming, winterisation bleaching and deodorization process.

• Degumming process removes trace metals, mucilage, dirt and phospholipids with the help of a degumming agent. The process is conducted via highly evolved continuous process with proper retention of oil along with phosphoric acid as well as other degumming reagents. This further facilitates the conversion of non-hydratable phospholipids to hydratable phospholipids which are easily removed through hydration followed by centrifugal separation.

• The next step is bleaching which involves the selective removal of impurities and pigments via chemical and physical interaction of absorbent with fat or oil for improving its quality.

• This process helps in the removal of –

a. Trace metals and Dirt

b. Phospholipids

c. Colour pigments

d. Polycyclic aromatic compounds

• In order to remove undesired colorants from oils and fats, bleaching process is undertaken. These undesired colorants disturb the appearance of the product and negatively affect the taste of the oil.

• In addition, the bleaching process also removes the pigments or particles which promote deterioration of oil quality. This mainly occurs as a result of pro-oxidative properties which promotes oxidation

• Deacidification cum Deodorization is a vacuum stripping process. In this process a certain amount of stripping agent which is usually steam is passed through hot oil at quite a low pressure for a certain period of time. It is basically a physical refining process in which various volatile components are removed but the process is conducted at high temperature, so few thermal or chemical effects may occur.