SOYBEAN (Glycine soja)

Seeds

Importance and grain composition:

Soybeans are used in food industry as well as for feed production. For human nutrition purposes, oil, flour, sauces, milk, tofu cheese and soy meat are produced from soybeans. In the feed industry, whole soybeans are used, but more often by-products from fat processing, soybean cake or soybean meal are used. Whole full fat soybeans are used mainly in the diets for high–producing dairy cows. They markedly increase energy value of the diet. Soybean cake and extracted meal are used as protein sources in compound feeds for all the farm animals and partly they replace animal origin feeds even in some complete feeds for carnivores.

Whole soybeans have, due to a high fat content (15-20%), the highest energy value of all the legumes. Fat contains a lot of unsaturated fatty acids, the essential linoleic acid makes up about 50%. Soybean also has a high content of crude protein (35-40%). Proteins have high biological value, high content of essential aminoacids, they contain most lysine of all the legumes. Therefore they are used for the production of structural protein that can be wowen to form soya meat. Nitrogen-free extract is about 25%, crude fibre 4-7% and mineral substances about 3%.

Soybeans also contain antinutritional substances. These include antigenic proteins that may induce food allergies, and trypsin inhibitors that block digestive enzymes, thereby decreasing protein availability. Trypsin inhibitors are thermolabile, that is why soybeans is treated by toasting or extrusion.

 Cultivation requirements:

Soya is a thermophilic crop, and it is moisture intensive. In the period of blooming and seed swelling, rainfall is very important. Soya requires deep, biologically active soil, warm and well supplied with nutrients. It does not tolerate heavy, waterlogged and acid soils. It is not demanding as regards a previous crop. Suitable previous crops are root plants, cereals are all right. In this country mainly early Canadian soybean varieties are grown.