Soybean is one of the major protein resources mainly in east-Asian countries, and its benefit to health is calling attention, Soybean is used broadly for fermented, or unfermented food, especially tofu, gelatinized curd, and its derivative products like Abura-age (thin, deep-fried tofu), or Kari-tofu (freeze-dried tofu) are typical usage. Gelatinization quality is crucial for soybean utilization. Though many studies have been conducted on the formation of tofu gel from soymilk and soy proteins, the effect of each protein component soybean on the tofu gel quality has not been elucidated. We analyzed d1e disulfide bonds in soybean protein using a fluorescence labeling method and investigated its relationship to soybean processing quality. As well as established functions of protein components, such as major proteins and isoflavones, studies have been carried out on novel functional quality of proteins, peptides and other components for the future food development.