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Introduction
Activated carbon is a porous substance with a large specific surface area, so it has excellent adsorption capacity. In the soybean oil production process, adding activated carbon can effectively adsorb and remove pigments, impurities and substances that may cause odor in the soybean oil. This can significantly improve the clarity and taste of soybean oil, making it more in line with consumer expectations.
Soybean oil decolorization process
Soybean oil decolorization is one of the most important steps in the soybean oil refining process. Its purpose is to remove impurities, pigments and other harmful substances in soybean oil by selecting appropriate decolorizers, thereby improving the quality and nutritional value of soybean oil. The main process flow of soybean oil decolorization is as follows:
(I) Material cleaning:
Generally speaking, soybean oil is first filtered through multiple filters to remove impurities. This can effectively reduce the consumption of activated carbon and extend its service life.
(II) Heating and dehydration:
The filtered soybean oil is heated to 70℃-90℃ for dehydration to reduce the moisture content, reduce the oleic acid value, and help the adsorption of activated carbon.
(III) Decolorization:
Activated carbon is placed in the decolorization tank, and then the heated and dehydrated soybean oil flows into the tank. Activated carbon absorbs pigments and impurities in soybean oil, making the soybean oil purer. The decolorization time varies depending on the manufacturer, ranging from 20-40 minutes to 60-120 minutes.
(IV) Filtration:
The decolorized soybean oil needs to be filtered to remove residual activated carbon and other impurities. The purpose of filtration is to ensure that the transparency and rheology of soybean oil meet national standards.
Activated carbon application
Highly efficient pigment adsorption capacity
Soybean oil contains natural pigments, such as carotenoids, chlorophyll, etc., as well as oxidation products and trace impurities produced during processing, which will affect the color of the oil. Activated carbon can effectively adsorb pigment molecules in the oil due to its developed pore structure and high specific surface area.
Activated carbon can capture these pigment particles and impurities through its microporous and mesoporous structure, making the color of the oil clearer and more transparent. In addition, compared with other decolorization methods, such as using bleaching earth, activated carbon has a higher decolorization efficiency and can more effectively remove stubborn pigments that are difficult to handle.
Remove odor and oxidized substances to improve oil stability
In addition to decolorization, activated carbon also has the ability to remove odor and oxidation products. Oils and fats are prone to produce some odors during storage, especially edible oils containing more unsaturated fatty acids. Activated carbon can absorb these odor molecules through its pore structure, so that the oils and fats maintain a purer flavor.
At the same time, during the decolorization process, activated carbon can also absorb some free fatty acids and oxidation products in the oils and fats, thereby delaying the oxidation and deterioration of the oils and fats, and improving the stability and shelf life of the oils and fats. This is particularly important for improving the quality of edible oils.
Comply with food safety standards to ensure the health of oil products
As a food, the safety of edible oil is of vital importance. As a food-grade decolorization material, activated carbon complies with relevant food safety standards and will not introduce harmful components to oil during the decolorization process. Its physical adsorption process does not produce chemical reactions and is easy to be completely removed by filtration, ensuring the purity and health of refined oil.
This high safety and non-toxicity make activated carbon widely used in the edible oil industry, enhancing consumers’ confidence in refined oil products, and also helping manufacturers establish a good brand image in the market.
How to choose the right activated carbon？
In the refining process of soybean oil, decolorization is a crucial step. Wood powder carbon and MgO impregnated activated carbon are two commonly used decolorization adsorption materials. The following will introduce the action mechanism and key parameters of the two materials respectively.
Wood Activated Carbon Powder
• Mainly relying on physical adsorption, its developed microporous structure and high specific surface area can effectively adsorb small molecular pigments (such as chlorophyll, carotene) and partial oxidation products in oil products.
• Suitable for treating light-colored oil products and will not change the chemical properties of the oil products.
| Item | Indicators |
| Patical Size | 200 mesh pass ≥96% |
| Iodine | 700-1100 mg /g |
| Methylene blue adsorption | 100-240 mg/g |
| Ash | 5-12 % |
| Moisture | ≤ 5% |
| PH Value | 3-5 |
| Filling the proportion | 0.38-0.50 g/cm3 |
MgO Activated Carbon
• Combining physical adsorption and chemical adsorption, the alkaline properties of magnesium oxide can neutralize free fatty acids and polar impurities in oil products, while adsorbing dark pigments (such as oxidation products and polar pigments).
• It shows stronger comprehensive performance in dark oil or acidic oil treatment.
| Item | Indicators |
| Surface area | 1000m2/g min |
| MgO content | 5%-15% |
| Iodine value | 900mg/g min |
| Size | 8*30 or 12*40mesh |
| Moisture | ≤ 5% |
| PH Value | 8-11 |
| Ash | 10-12% |
Conclusion
Activated carbon has unique advantages in soybean oil decolorization. Different types of activated carbon (such as wood powder carbon and MgO impregnated activated carbon) can provide optimized solutions according to the characteristics of the oil and decolorization requirements. Reasonable selection and application of activated carbon can not only improve the appearance and quality of soybean oil, but also meet the market’s strict requirements for high-quality oil products.
If you have any needs for oil decolorization, please contact us in time.