There will be a certain loss of phytosterols in the traditional oil processing process. In order to avoid the waste of natural resources, it needs to be extracted from the by-products of oil processing and used for other purposes.

The deodorizer distillate (DD oil) generally contains 6% ~ 10% phytosterols, mainly in the form of free sterols, accounting for about 80% of the total sterols, and the acid oil is dominated by bound sterols. The content and form of phytosterol in raw materials are different, which determines the extraction process of phytosterol. In the phytosterol production industry, DD oil and residual oil are mainly used as raw materials, through acid-base esterification and crystallization methods; or acidic oil is used as raw material, through hydrolysis, acid-base esterification and crystallization methods.

Phytosterols were extracted from DD oil for industrial production, and the production process was as follows: DD oil → esterification → cold precipitation → alcohol washing and refining → phytosterols. The refining of phytosterol mainly includes two processes of beating and hot dissolving, beating is generally carried out in two times, but due to the reasons of phytosterol transportation, in order to reduce the labor intensity of workers, many factories adopt a beating method, the ratio of phytosterol and ethanol is 1: 10. Hot dissolution is the use of phytosterol insoluble in cold ethanol and soluble in hot ethanol characteristics to achieve the separation of phytosterol and methyl esters and other impurities. Because the content of phytosterols in the acid oil is not as high as that in DD oil, and the combined sterols are the main method, the current acid oil to produce phytosterols is to convert the combined sterols into free sterols by high-pressure hydrolysis, and the rest of the process is the same as that of DD oil extraction. The phytosterol was extracted from the acid oil, and the total sterol and free sterol content in each process of acid oil hydrolysis were shown in the table.