Soybean (Glycine max) is a legume included in the Fabaceae family and classified as an oilseed. It is a plant of Asian origin, autogamous and photoperiod-sensitive. Autogamy has allowed the development of GMO varieties in the USA. There are from short-season (90 days) to very-long-season (200 days) varieties. Although the growing of the GMO varieties is not allowed in the EU, their commercialisation is allowed.
Soy-bean oil cake is the most quality plant raw material for production of combined fodders and is a protein base of the fodders. It is recommended to include up to 35 % of soy-bean oil cake to main ration of all types of agricultural animals, birds, and fishes. Soy-bean protein by its biological properties is close to proteins of animal originand due to this is well digested by organism of animals.
Soy-bean oil cake is produced from seeds of a very nutritive culture of soy in the process of oil production. During processing oil is obtained only from “oily” part of seeds, while eatable “leaves” of seeds remain in wastes. These leaves are soy-bean oil cake which besides protein and amino acids contains a lot of different mineral substances: Ca, P, Fe, Mn, Zn, etc.
There are 3 main processes to extract soybean oil:
- The most common process consists in extracting oil from soybean flakes by solvent. In the USA, virtually all soybeans (99%) are solvent-extracted. This method is the most efficient and about 1.5% oil is left in the resulting soybean meal.
- The second method consists in a mechanical extraction by a screw press (expeller). This method yields less oil and a soybean meal containing more than 5% residual oil.
- The third method combines extruding and expelling of soybean flakes, and uses solvent for oil extraction (Johnson et al., 2018).
Before extraction, the soybean seeds undergoes differents treatments aimed at increasing oil extraction and soybean meal quality.
The main application of soybean oil cake is as a feed additive. The high content of energy and protein in oilcake allows to make high protein and high energetic ratio without the use of expensive fat. The inclusion of soybean oilcake in the dairy cows' ratio (1-2 kg per head per day) increases the milk yield to 1.5-2.0 liters. Laying hens egg production increases up to 22-30%, chicken growth increases by 7%, pigs — 5%, broilers` and pigs` body weight increase up to 25-30% in comparison with the normal feeding.