The process of producing edible oil includes leaching and pressing.

The price of edible oil squeezed out by different processes will be different. The price of leaching oil is lower than that of pressed oil.

In the process of leaching, there will be some residual residue in the final product, which is within the permissible limits of the national standard.

The edible oil produced by this process has the advantages of large output and low price.
 

Squeezing is a kind of physical squeezing method, which can extract the fat from the raw material, and does not require the addition of any chemical solvent.
 

The yield of edible oil obtained by this method is lower than that of leaching, and it is more expensive.

The Crude Oil Refining Methods Include:
 

1. Mechanical Method: Including sedimentation, filtration, and centrifugal separation, which is mainly used for the separation of certain digestive impurities suspended in the oil from mechanical impurities;
 

2. Chemical Method: mainly includes acid refining and alkali refining, in addition to fatification, oxidation, etc. Acid refining is treated with acid to remove pigments and peptic impurities, and alkali refining is treated with alkali to remove free fatty acids. Oxidation is mainly used for decolorization.
 

3. Physical and Chemical Methods: mainly include hydration, decolorization, steam distillation, etc. Hydration mainly removes phospholipids, decolorization mainly removes pigments, and steam distillation is used to remove odorous substances and free fatty acids.