"Soya" (or "Soy" in the United States), is a legume, Glycine max (L.) Merrill. Soy has been grown for three millennia in Asia and, more recently, has been successfully cultivated around the world. Today, the world’s top producers of soy are the United States, Brazil, Argentina, China and India.
About 85 percent of the world’s soybeans are processed, or "crushed," annually into soybean meal and oil. Approximately 98 percent of the soybean meal that is crushed is further processed into animal feed with the balance used to make soy flour and proteins. Of the oil fraction, 95 percent is consumed as edible oil; the rest is used for industrial products such as fatty acids, soaps and biodiesel.
Soy is one of the few plants that provides a complete protein as it contains all eight amino acids essential for human health.
The first written reference to soy appears in a list of Chinese plants from 2853 B.C.; it is also referred to many times in ancient writings as one of the five grains essential to Chinese civilization. Western contact with soybeans and soyfoods was limited until Asians began to emigrate in large numbers to Europe and the U.S. in the 1800s.
Large-scale development of soybean production and processing in the U.S. began during the 1940s and 1950s spurred on by a rapid increase in both domestic and worldwide demand for protein meal and oil. Harvested acreage for soybeans in the U.S. more than tripled between 1940 and 1955, from 4.8 million acres to 18.6 million, while total production of soybeans increased nearly five-fold, from 78 million bushels to 374 million.
As the number of acres devoted to soybeans continued to grow during the 1960s, the United States became a world soybean superpower and began exporting large quantities of soybeans, as well as meal and oil, to Europe and Asia. Industry growth has slowed in recent years with increased competition, but the U.S. still produces (in the early years of this century) roughly 75 million metric tons of soybeans each year.