Fermented vegetable (soybean) protein and related foods of Japan and China

Main fermented vegetable protein foods in Japan and China are soy sauce (shoyu in Japan, chiang‐yu in China), fermented soy paste (miso in Japan, chiang in China), sufu, and natto, which are all traditional foods. Chiang, which originated in China some 2,500 years ago, was introduced into Japan during the seventh century and transformed into the present Japanese shoyu and miso, which are now quite different from their Chinese counterparts. Their fermentations consist of koji fermentation by Aspergillus species and the subsequent brine fermentation which contains lactic acid and alcoholic fermentations. The characteristic appetizing aroma observed in Japanese style of soy sauce (shoyu) is derived through a special brine fermentation from the component of the wheat which constitutes about one‐half of the materials. During the recent two decades, the fermentation technology and engineering on shoyu and miso have made great progress in Japan. Sufu (Chinese soybean cheese) is a cheese‐like product originating in China in the fifth century. It is made through the fermentation by Mucor or a related mold from soybean protein curd called “tofu,” which is made by coagulating soy milk. This product is widely manufactured in China on a small scale, but it is not made and consumed in Japan. On the other hand, natto is the fermented soybean protein food characteristic in Japan. It is a whole soybean product fermented by Bacillus species, and was originated in Northeastern Japan about 1,000 years ago. Natto is served as it is with shoyu and mustard. Besides these traditional fermented foods, a new fermented soybean product appeared on the market recently in Japan. It is a soy milk drink fermented by lactic acid bacteria. Recently, fermented soy sauce is penetrating into Western populations widely, particularly in the United States. The possibility for the universalization of traditional food flavors is discussed.