The Six-Step Process for Refining Soybean Oil

With the improvement of people's living standards and health awareness, the demand for high-quality edible oils is continuously increasing. As one of the high-quality edible oils, Grade 1 soybean oil has a broad market prospect. By implementing a soybean oil refining project, high-quality soybean oil that meets market demand can be produced, bringing considerable economic benefits to enterprises.

The refining of first-grade soybean oil requires multiple processing steps, mainly including:

1. Hydration Degumming:

Adding a certain amount of hot water or acid, alkali, salt, and other electrolyte solutions to crude soybean oil. Utilizing the hydrophilicity of phospholipids and other lipid molecules, colloidal impurities absorb water, swell, and coagulate, thus precipitating and separating from the oil. This step effectively removes phospholipids and other impurities from the oil, improving its stability.

2. Alkali Refining and Deacidification: 

Neutralizing free fatty acids in crude oil with caustic soda solution to form sodium soap, which precipitates and separates from the oil. Alkali refining not only removes free fatty acids but also some phospholipids, proteins, mucilage, and other impurities, improving the oil's quality.

3. Vacuum Drying:

 During the refining process, the oil contains a certain amount of water. Vacuum drying removes water from the oil, preventing hydrolytic rancidity during storage and transportation.

4. Adsorption Decolorization: 

Using adsorbents with strong selective adsorption for certain pigments in the oil to remove pigments and other impurities under certain conditions. Adsorption decolorization not only improves the oil's appearance but also removes trace metals, residual soap, phospholipids, and other impurities.

5. Vacuum Deodorization: 

Utilizing the significant difference in volatility (vapor pressure) between triglycerides and odor substances affecting the oil's smell, color, and stability. This process removes odor substances through high temperature and vacuum conditions using steam distillation. Deodorization improves the oil's edible quality by removing odor substances.

6. Winterization:

 Based on the difference in melting points between wax and oil and the decreasing solubility of wax in oil with temperature reduction, cooling crystallizes the wax, which is then separated by filtration. Winterization removes wax from the oil, improving its transparency and stability.

The six-step refining process removes most impurities from the oil, enhancing the quality and color of soybean oil and extending its shelf life. Each batch of refined soybean oil undergoes sampling and testing. Only when the test results meet the standards for Grade 1 soybean oil can it be sent to the next workshop for filling and sealing, awaiting market delivery. If the test results are unqualified, the oil must be returned to the refining process for reprocessing.