Sunflower oil is a widely used vegetable oil, which is popular for its high content of unsaturated fatty acids and vitamin E. The process of refining sunflower oil starts with using crude sunflower oil as raw material, and finally obtains refined finished oil after a series of processing steps. Specifically, after the crude oil is preheated, an appropriate amount of light alkali is added to react with the gum impurities and some free fatty acids in the oil to form soap stock. Subsequently, the soap stock is separated. In order to further remove the gum impurities in the oil, the oil is washed several times with hot salt water, and the soap washing water is separated. This article will introduce the refining process of sunflower oil in detail.

The necessity for refining of sunflower oil:

The oil obtained through the pressing process is called crude oil. Crude oil contains some impurities such as phospholipids, free fatty acids and pigments. In order to improve the quality of oil, these impurities need to be removed in the subsequent refining process. Impurities in crude oil not only affect the appearance and taste of the oil, but may also be harmful to health. Therefore, the main objective of the refining process is to remove these impurities and improve the purity and stability of the oil.

Sunflower oil refining mainly has the following processes.

(1) Degumming section

Gum soluble impurities in sunflower oil not only affects the stability of the oil, but also affects the oil refining and deep processing of the process results. Colloidal impurities will make the oil in the process of alkali refining emulsification, increase operational difficulties, increase the loss of oil and lye, and reduce the quality of the soap foot; in the decolorization process, colloidal impurities will also increase the adsorbent consumption, reduce the decolorization effect.

(2) Deacidification section

Deacidification section is mainly used to remove free fatty acids in sunflower oil. There are always some free fatty acids in the oil, the amount of which depends on the quality of the oil. The immaturity of seeds, high breakage of seeds and so on are the causes of high acid value oil, especially under high moisture condition, which is unfavorable to the preservation of oil, which will make the content of free fatty acid rise and reduce the quality of oil, deteriorate the edible quality of oil, so it is necessary to remove the free fatty acid.

(3) Decolorizing section

The pigment in sunflower oil is complex, mainly including chlorophyll, carotene, flavonoid pigment, flower pigment and some sugar, protein decomposition products and so on. Sunflower oil decolorization commonly used adsorption decolorization method. The principle of adsorption decolorization method is to use the adsorbent with strong adsorption in the hot oil can adsorb pigments and other impurities, in the filtration to remove the adsorbent at the same time also be adsorbed pigments and impurities removed, so as to achieve the purpose of decolorization and purification.

(4) Deodorization section

Sunflower oil by deacidification, decolorization treatment will also have trace aldehydes, ketones, hydrocarbons, low molecular lipids, glycerol phenol oxides, as well as white earth, residual solvent odor, etc., to remove these odors of the process is called deodorization section. Deodorization, the first to the oil into the high-temperature direct steam, the use of oil and odor substances between the volatility of the difference to remove these substances, so as to complete the deodorization.

(5) Dewaxing section

The wax in sunflower oil will affect the flavor and taste of the oil, which needs to be dewaxed. There are many methods for dewaxing, such as freezing crystallization method, surfactant method, cold polymerization method, electrostatic method, neutralization and winterization method. However, at present, freeze crystallization method is basically used in the production of edible oil. The specific dewaxing process operation also needs to be set according to the wax content of sunflower oil and market requirements, and after dewaxing, sunflower oil can be obtained in accordance with the specified standards.

Conclusion:

The refining process of sunflower oil includes multiple steps, each of which has an important impact on the quality of the final product. Through refining, impurities in the oil can be removed, and the purity and stability of the oil can be improved, thereby ensuring its safety and nutritional value in cooking oil.