Soybean (Glycine max) is an oil-protein plant cultivated for its seeds rich in protein (27-50%) and fat (17-27%). The plant is used in human nutrition, in obtaining compound feed, for the production of flour, for the extraction of fats or for the production of milk, sauces or soups. The characteristic protein of soy is glycine. It is easily digestible and is very close to the characteristics of animal protein. The fats in soybeans are: palmitin, stearin, olein, linolein, phytosterol, cholesterol and lecithin. Soybean oil contains 75-85% unsaturated fatty acids.
The cultivation of the soybean plant began in East Asia and spread all over the world. It is cultivated in large quantities in Romania, being very profitable and an excellent predecessor for other crops, leaving the soil rich in nitrogen.
Both seeds and pods and young plants are used in the diet. Soybeans produce a wide range of products - vegetable milk, vegetable cheese, coffee substitute, chocolate, soy flour can be obtained from bakery products, and soybean oil is used in cooking and salads, but also for margarine production. Protein fibers from soybean meal are used to obtain "vegetable meat" with which a lot of other products are prepared - pies, sausages, etc. The plant is very valuable in animal feed, and soybean oil is also used in the production of soaps, paints, plastics. Worldwide in the production of soybean vegetable oil ranks second, after the palm oil
Soy is used in the production of food, feed and fuel, but also for industrial purposes. By crushing oilseeds, oil and flour are obtained. Vegetable oil is generally used in the food industry or to produce biodiesel, while oilseed meal is an important component of animal feed.
There are 3 ways to extract soybean oil and grits from soybeans:
The most commonly used worldwide is solvent extraction - most soybeans are extracted with solvent. This method effectively extracts grain oil and only 1.5% residual oil can be found in soybean meal.
The second method consists in the mechanical extraction of soybean flakes with a screw press to extract the oil, without using any solvent. This produces less oil and a high-fat soybean meal. The third method combines the extrusion and expulsion of soybean flakes and none of them uses a solvent to extract the oil.