soybean

A soybean field in Brazil, a principal producer of soybeans. The soybean is one of the richest and cheapest sources of protein, a staple diet for many millions of people across the world. It can be eaten in a number of different forms, including as soya milk and as tofu. In China, it is used as a food and in medicines.

The grain of the soybean plant. The soybean is one of the cheapest and best sources of vegetable protein, and a staple part of human and animal diets in many parts of the world. The bean's many different uses – from its great versatility in food products to its industrial applications – make it, economically, the most important bean worldwide.

Leguminous plant (see legume), native to East Asia, in particular Japan and China. Originally grown as a food crop for animals, it is increasingly used for human consumption in cooking oils and margarine, as a flour, soya milk, soy sauce, or processed into tofu, miso, or textured vegetable protein (TVP). (Glycine max)

Soya is the richest natural vegetable food. The dried bean is 18–22% fat, 35% carbohydrate, and one hectare of soybeans yields 162 kg/357 lb of protein (compared with 9 kg/20 lb per hectare for beef). There are more than 1,000 varieties. The plant has been cultivated in Asia for about 5,000 years, and first became known in Europe when brought back from Japan by the German botanist Engelbert Kaenfer in 1692. Today the USA produces more soybeans than Asia.

Miso is soybeans fermented with cereal grains, water, and salt, used in soups and sauces; soy sauce is beans fermented with salt; and tamari is similar to soy sauce but stronger, having been matured for up to two years.

Soybeans are rich in the plant hormones phytoestrogens that in the human body seem to act to dilute the impact of the body's own oestrogens. As exposure to too much oestrogen increases the chances of developing certain cancers, particularly that of the breast, high consumption of soya products could provide some protection. US biochemists isolated the component in soybeans that helps to prevent cancer, in 1998. The plant oestrogen genistein has been proved in laboratory tests to be able to prevent growth in cancerous tumours.

The European Patent Office granted a patent to the US company Agrecetus in 1994 to cover all forms of genetically engineered soybean plants and seeds.