Crude oil contains colloidal impurities, free fatty acids, pigments and other impurities, which will affect the quality of edible oil. China has clear standards for the quality of cooking oil. Especially recently we have strengthened spot checks on cooking oil, and we should pay more attention to it.
Refining edible oil requires edible oil refining equipment. The working principle of edible oil refining equipment is closely related to the types and characteristics of these impurities, which will be introduced in detail below.
Crude oil contains colloidal impurities such as phospholipids and proteins, which affect the stability of oil and the refining and deep processing of oil. These colloidal impurities are hydrophilic, agglomerate after absorbing water, and precipitate colloids after settling. Therefore, we can remove them by water degumming.
If the edible oil is not degummed in time, the crude oil will be easily emulsified in the subsequent deacidification process, which will increase the loss of refining and auxiliary materials, reduce the quality of saponins, and increase the loss of adsorbent (clay).
During the decolorization process, the decolorization effect is reduced. Degummed oil cannot be physically refined and deodorized, and cannot be further processed.
In addition to colloidal impurities, crude oil also contains free fatty acids, which will affect the quality, taste and storage time of refined oil.
We can remove them by physical or chemical deacidification. Physical deacidification refers to the removal of free fatty acids by the chemical principle of acid-base neutralization, and chemical deacidification refers to the removal of free fatty acids by the principle of steam distillation.
In addition, crude oil contains some pigments, which will affect the color of cooking oil. We can use the adsorption of clay to remove pigment and make refined oil more clear and transparent.
Impurities with peculiar smell will also exist in crude oil, affecting the taste and quality of edible oil. We can use the principles of these odorous impurities and oil volatility to remove odors.
Finally, in addition to degumming, deacidification, decolorization, and deodorization, some edible oil refineries will also perform dewaxing operations to remove wax in oils and fats, thereby obtaining high-quality edible oils, which can be used to refine sunflower seeds and other high-wax content. Cooking oil, rice bran oil and corn oil.