Nutritionally, tofu is low in calories, while containing a relatively large amount of protein. The earliest documentation of the word in English is towfu, in a 1770 letter from the English merchant James Flint to Benjamin Franklin. United States since at least 1840. Tofu making was tofu banh mi calories recorded during the Chinese Han dynasty about 2000 years ago.
It spread to other parts of Southeast Asia as well. The most commonly held of the three theories of tofu’s origin maintains that tofu was discovered by Lord Liu An, a Han Dynasty prince. While plausible, the paucity of reliable sources for this period makes this difficult to conclusively determine. Another theory suggests that the production method for tofu was discovered accidentally when a slurry of boiled, ground soybeans was mixed with impure sea salt. Such sea salt would probably have contained calcium and magnesium salts, allowing the soy mixture to curdle and produce a tofu-like gel. The last group of theories maintains that the ancient Chinese learned the method for curdling soy milk by emulating the milk curdling techniques of the Mongolians or East Indians.
Despite their advanced culture, no technology or knowledge of culturing and processing milk products existed within ancient Chinese society. Although intriguing and possible, there is no evidence to substantiate this theory beyond academic speculation. In China, tofu is traditionally used as a food offering when visiting the graves of deceased relatives. Before refrigeration was available in China, tofu was often only sold during winter since tofu did not spoil as easily in cold weather. The earliest Japanese document concerning tofu refers to the dish being served as an offering at the Kasuga Shrine in Nara in 1183. 1782 of the Edo period, lists 100 recipes for cooking tofu.