Soybean seeds contain high-quality proteins that are used as a source of food, and also abundant lipids that are used as a vegetable oil. Many functional ingredients are also included in soybean seeds. We have identified qualitative and/or quantitative genetic variations in several components, such as protein, α-tocopherol, chlorophyll, and isoflavone, among soybean genetic resources. These genetic variations are available to improve the processing properties and to add some values for soy foods. We also demonstrated that a high and low temperature during seed filling enhanced the biosynthetic pathways of α-tocopherol and isoflavone, respectively. These suggest that it is possible to increase the amounts of functional components, such as α-tocopherol and isoflavones, by improving the cultivation environment of soybean in addition to the development of new soybean varieties by using genetic variations. The successful use of genetic variations and physiological properties related to soybean quality will not only enable differentiation from conventional soy products, but also create new uses for soybean.
