The soya bean, Glycine max (L.) Merr., belongs to the Papilionaceae family, Fabaceae (Legminosae).
This annual plant grows upright up to 100 cm. Most varieties are limited in growth and are self-fertile. However, bees and other pollinating animals also have a positive influence; there is even species-pure honey. The soya bean is a short-day plant, meaning that the dark/night phase must be long enough for floral development.
A typical botanical feature of the soya bean is a cygomorphic, papilionaceous flower with a corolla consisting of keel, banner and wings and the 10 stamens fused together into a tube. The flower corolla is very small, only slightly longer than the calyx and, thus, rather innocuous. Its colour ranges from white to purple. Three to eight, sometimes even 12, flowers grow in the leaf axils.
The soya bean has trifoliate leaves with long petioles. Additionally, the individual, egg-shaped leaflets have petioles, with the leaflet at the end having a longer petiole than those at the sides. The leaf surface is very hairy on both sides, in particular around the edges and on the veins of the bottom side.
The fruit is made up of 3-5 (8) cm long and 10 mm wide, hairy pods with usually 2-3 seeds in it. The round to oval seeds are smooth and range from yellow to brown in colour.
The soya bean is especially important for its protein content and composition. The seeds contain 33-44 % pure protein and the essential amino acids isoleucine, leucine and lysin, the essential sulphur-containing amino acids methionine and cysteine, phenylalanine, tyrosine, threonine, tryptophan and valine, as well as the non-essential amino-acids arginine, histidine, alanine, aspartic acid, glutamic acid, glycine, proline and serine. The carbohydrate level is approximately 30 %. The seeds’ raw fat content is between 17-21 % -- 48-52 % of which is made up by polyunsaturated linoleic acid and 23-32 % by monounsaturated oleic acid. In addition, the bean contains mostly B vitamins and vitamins A, C, E and K. Minerals encompass potassium, phosphor, calcium and magnesium, while iron, zinc, manganese, copper, fluoride and iodine are trace elements.