Soybeans comprise approximately 8% seed coat or hull, 90% cotyledons and 2% hypocotyl axis or germ.
100 grams of raw soybeans supply 446 calories and are 9% water, 30% carbohydrates, 20% total fat and 36% protein (table).
Soy vegetable oil, used in food and industrial applications, is another product of processing the soybean crop. The first stage of growth is germination, a method which first becomes apparent as a seed's radicle emerges.
Before flowering, roots can grow 1.9 cm (0.75 in) per day.
Remarkably, seeds such as soybeans containing very high levels of protein can undergo desiccation, yet survive and revive after water absorption. Carl Leopold, son of Aldo Leopold, began studying this capability at the Boyce Thompson Institute for Plant Research at Cornell University in the mid-1980s.
He found soybeans and corn to have a range of soluble carbohydrates protecting the seed's cell viability.
Soy is a good source of protein, amongst many others, for vegetarians and vegans or for people who want to reduce the amount of meat they eat, according to the US Food and Drug Administration: Soy protein products can be good substitutes for animal products because, unlike some other beans, soy offers a 'complete' protein profile. Soy protein products can replace animal-based foods—which also have complete proteins but tend to contain more fat, especially saturated fat—without requiring major adjustments elsewhere in the diet.
The Protein Digestibility Corrected Amino Acid Score (PDCAAS) of soy protein is the nutritional equivalent of meat, eggs, and casein for human growth and health.