Scientists with USDA's Agricultural Research Service compiled the database. It gives values for the major isoflavones in 128 soyfoods and ingredients. Isoflavones, such as daidzein, genistein and glycitein mimic the hormone estrogen. Often they ask if they can use soybeans grown on the farm they live on or near, or if there is a special type of soybean they should use. Although it is possible to use virtually any type of soybean to make soyfoods, there are special varieties of soybeans that are grown just for food use.
Soybeans vary greatly in both physical appearance and chemical composition.
Physical appearance includes size, shape, skin and hilum color. Hilum refers to the scar or notch found on soybean seeds. Compositional differences include protein and oil content, proportions of different proteins, fatty acid composition, and other minor constituents, such as isoflavones. All these differences can affect the yield, visual appearance, texture, taste, nutritional value, and health benefits of soyfoods. Just like different wheat products require different types of wheat as starting material, different types of soy products require different soybeans.