Research progress and potential application of Thua Nao

Thua Nao is a fermented soybean food widely consumed by people of northern Thailand. Similar products include Japanese Natto, Chinese Douchi, Korean Chongkukjang, and Indian Kinema. In Thailand, the production of Thua Nao tends to be prepared by a small-scale, home-made fermentation. Typically, the soybean seeds are soaked, boiled, fermented spontaneously by various microorganisms, and incubated at room temperature. Microbial starter cultures have been characterized, showing that Bacillus bacterial species have played an essential role for the fermentation. There is a good demand for this ethnic food among local consumers because of its nutritive and functional benefits. Besides, compared to other similar products, there is little scientific information on Thua Nao. In the present review, the latest knowledge of Thua Nao is summarized, including nutritional information, fermenting microbes, and product development. Furthermore, this article also explores the health benefits and potential applications of Thua Nao.