Abstract
Tofuyo is an indigenous fermented tofu in Okinawa, Japan. Red furu was brought to Okinawa from China, and was introduced during the period of the Ryukyu dynasty, around the 18th century. Because the product was brined and had strong taste, it was initially unpalatable to the Okinawan people in its original form. Therefore, it was re-created using awamori instead of salt by cooks in the dynasty for a more palatable taste that was milder in .avor. Microorganisms commonly used to the manufacturing of tofuyo belong to the genus Monascus and Aspergillus oryzae. The main components forming the body of tofuyo consist of basic subunit of glycinin and other polypeptides (Mr. 10,500-15,000). They are related to the textures of tofuyo. The soybean proteins were digested into amino acids and peptides during maturation. The amount of free glutamic acid and aspartic acid greatly related to good taste of the product. Some of the peptides (IFL and WL) liberated from tofuyo inhibited the angiotensin I-converting enzyme activity that produces the vasopressor peptide. Both IFL and WL were highly preserved after treatment with gastrointestinal proteases. Furthermore, the systolic blood pressure of rats in the tofuyo group was significantly lower than that in control group. Therefore, tofuyo was expected to have an antihypertensive effect.
