The edible oil processed by the press or leaching plant is often also refined. This is because during the pressing and leaching process, edible oil may have harmful substances such as water, fatty acids, pigments, oxides, etc. remaining. Refining can remove these harmful impurities, while also retaining some beneficial substances such as tocopherols.
Common refining equipment includes degumming, deacidification, decolorization, deodorization, etc., these refining steps can make edible oil more transparent, stable and resistant to high temperatures, and can also improve its taste, nutritional value and storage stability. Therefore, according to the different quality requirements and uses of edible oil, unwanted and harmful impurities are removed from the oil through refining equipment to obtain refined oil that meets certain quality standards, which is why edible oil should be refined. Refined cooking oil has a number of advantages, which are summarized below:
1. The refined oil is in better condition.
The function of decolorization and deodorization in oil refining equipment is to remove the odor small molecules in crude oil and the pigment in oil, make edible oil more clear and translucent, and improve the flavor of oil. For example, sunflower oil has a high wax content, and dewaxing treatment is also required to avoid turbidity caused by wax precipitation after storage for a period of time.
2. Refined oil has a wider range of uses.
Edible oil processing is a very large industry, and as an industrial product, it needs to be considered to meet various needs in the later stage. There are many impurities in crude oil, and the storage time is short, so it cannot be used in high-temperature processes, such as frying, baking, etc., thus limiting the range of uses of oil. Compared with crude oil, which has a limited range of application, refined oil has higher purity and a wider range of applications, which is more in line with the needs of industrialization and easier to be standardized.
3. The refined oil food has higher food safety.
The refining process can remove impurities and toxins that are harmful to the human body in the raw materials, such as gossypol contained in cottonseed oil, which is toxic to reproduction and harmful to human health, so cottonseed crude oil must be refined to meet the standard of safe consumption.
4. More by-products are produced in the refining process.
Edible crude oil can produce phospholipids in the process of refining and degumming, which is a high value-added product and can be used as an emulsifier and stabilizer in food
Some vegetable oils can produce tocopherol (vitamin E) during the deodorization process, and vitamin E can be added to foods as antioxidants, delay the oxidation process of food, and extend the shelf life of food. In addition, vitamin E itself is a vitamin, and it is also widely used in the field of health care products and medicines
Some palm oil refineries will extract palm oil according to the different melting points of palm oil fatty acids to obtain palm stearin with a high melting point and solid at room temperature and palm soft grease with a low melting point and liquid at room temperature, so as to meet the needs of different subsequent processing scenarios of palm oil.