Cleaning of soybean
The soybeans are first cleaned, dried and dehulled prior to oil extraction. The soybean hulls needs to be removed because they absorb oil and
give a lower yield. This dehulling is done by cracking the soybeans and a mechanical separation of the hulls and cracked soybeans. Magnets are used to separate any iron from the soybeans.The soybeans are also heated to about 75°C to coagulate the soy proteins to make the oil extraction
easier.
Extraction of soybean oil
First the soybeans are cut in flakes which are put in a percolation extractors and immerged with a solvent, normally hexane. Counterflow is used as extraction system because it gives the highest yield. After removing the hexane, the extracted flakes only contain about 1% of soybean oil and
is used as livestock meal or to produce food products such as soy protein. The hexane is separated from the soybean oil in evaporators.
The evaporated hexane is recovered and returned to the extraction process. The hexane free crude soybean oil is then further purified.
Purification of soybean oil
The crude soybean oil still contains many oil-insoluble and oil-soluble impurities that needs to be removed. The oil
insoluble material are removed with filtration and the soluble materials is removed with different processes including degumming (removing of phosphatides), alkali refining (washing with alkaline solution to remove free fatty acids, colorants, insoluble matter and gums) and bleaching
(with activated earth or activated carbon to remove color and other impurities.
Hydrogenation of soybean oil (optional)
This process will increase the stability of the soybean oil and will make it less liquid. However, this process will create more saturated fats and
will reduce the favorable unsaturated fats. In addition, trans fats are produced which can cause health problems. Hydrogenated soybean oil is
used in foods that require more solid fat such as margarines.
Soybean oil production line features:
NO | Main workshops | Main equipment | Remarks |
1 | Soybean pretreatment workshop | Magnetic machine,vibration machine, cleaning sieve, dryer. | Cleaning and treating soybean for best solvent extraction-condition
|
2 | Soybean oil solvent extraction workshop | Rotocel extractor,Evaporator, Desolventizer
| Extracting the Soybean oil out |
3 | Soybean oil refinery workshop | Refining pot,bleaching tower, deodorizer
| Refining crude rice bran oil into edible ones
|
4 | Soybean oil bottling line | Filling machine, capping machine, labeling machine
| Bottling line |