Soybeans are 30 percent carbohydrate (of which 15 percent is fiber), 18 percent oil (85 percent unsaturated), 14 percent moisture and 38 percent protein. They are the only legume that contains the nine essential amino acids in the correct proportion for human health. Soy protein therefore is categorized as a high-quality, complete protein. Its nutrition benefits include being good sources of phosphorus, potassium, B vitamins, zinc, iron and the antioxidant vitamin E.

Processing the Bean

The figure below describes the processing of soy beans. 

Lecithin in Food:

Lecithin is a naturally-occurring group of phospholipids that's found in nearly every living cell. Though the word lecithin is derived from the Greek "lekithos", which means "yolk of an egg," the primary commercial source of lecithin as a food ingredient comes from the soybean.

The food industry has long recognized lecithin as a lipophilic emulsifier used in products like margarine and chocolate. But lecithin can be much more than that. Through specific modification techniques, industries have extended the functionality and physical characteristics of lecithin far beyond their natural limitations to include a wider range of functionalities like wetting, dispersion, lubrication, sprayability and ease of handling in dry powder form.

Lecithin Processing:

Lecithin is a combination of phospholipids that naturally occur in soybeans. Lecithin gums are obtained from soy oil after the oil has been extracted from the soybean flakes. Lecithin is removed from the soybean oil using a steam precipitation process. At this point, the gums contain about 25% moisture, 50% phospholipids and 25% soy oil. The gums are dried under a vacuum to about 65% phospholipid content. A wide variety of refined lecithins are made from this stock by filtration, blending, compounding, enzymatically or chemically modifying or deoiling.