Nattō

is a traditional Japanese food made from whole soybeans that have been fermented with ''Bacillus subtilis'' var. ''natto''. It is often served as a breakfast food with rice. It is served with ''karashi'' mustard, soy or ''tare'' sauce, and sometimes Japanese bunching onion. Within Japan, ''nattō'' is most popular in the eastern regions, including Kantō, Tōhoku, and Hokkaido.

''Nattō'' is often considered an acquired taste because of its powerful smell, strong flavor, and sticky, slimy texture. A 2009 survey revealed that 70% of the 3,827 respondents (0.003% of the population) found the taste pleasant, and others who may not find the taste pleasant still eat the food out of habit.

History

Sources differ about the earliest origin of ''nattō''. One theory is that nattō was codeveloped in multiple locations in the distant past, since it is simple to make with ingredients and tools commonly available in Japan since ancient times.

Legendary origins

One story about the origin of ''nattō'' attributes it to the samurai Minamoto no Yoshiie (1039–1106), who was on a campaign in northeastern Japan between 1086 and 1088 AD. One day, his troops were attacked while boiling soybeans for their horses. They hurriedly packed up the beans, and did not open the straw bags until a few days later, by which time the beans had fermented. The soldiers ate it anyway, and liked the taste, so they offered some to Yoshiie, who also liked the taste.

Another story involves Prince Shotoku (574–622), who is said to have wrapped the leftovers of boiled soybeans in straw bags for his horse. As people happened to eat these fermented beans and found them delicious, this type of fermented stringy beans soon gained popularity in Japan because of its unique taste and strong flavor.

Chinese ''douchi''

Before ''nattō'', there was a similar dish of fermented black soybeans food in China called ''shì'', ''chǐ''( zh, c=豉), or ''douchi'' (). These are salted, fermented and aged whole soybean seasonings or condiments invented in China and spread throughout East Asia. They are usually made from fermented soybeans and with an ample amount of salt; however, the ingredients and production methods differ in Japan. Chinese use both black and yellow soybeans to produce ''douchi''. The amount of salt used also differentiates ''douchi'' and ''nattō'' in taste and appearance.

The cultivation methods of soybeans and rice were imported from China to Japan during the Yayoi period, and later on, the circulation of salt began to flourish in Japan. This provided an opportunity for the production of ''douchi'' to become popular in Japan. Because salt was expensive at the time, it has been suggested that ''nattō'' was invented by accident during the production of ''douchi.''

A wooden slip was excavated in Heijō-kyō, which had the Chinese character 豉 (chǐ; soybean) written on it. The excavation of the slip is considered an evidence to support the hypothesis that the invention of ''nattō'' was based on the Chinese ''douchi'' imported to Japan.

The Chinese character 豉 entered Japan in the 8th century. It was pronounced "kuki" until the 11th century, when ''nattō'' became a new name for fermented soybeans.

Commercialization in the Taisho period

A change in the production of ''nattō'' occurred in the Taishō period (1912–1926), when researchers discovered a way to produce a ''nattō'' starter culture containing ''Bacillus subtilis'' without the need for straw, thereby simplifying the commercial production of ''nattō'' and enabling more consistent results.

Nutrition

Nattō is 55% water, 13% carbohydrates, 19% protein, and 11% fat (table). In a serving, nattō supplies 110 calories and is a rich source (20% or more of the Daily Value, DV) of several dietary minerals, especially iron (33% DV) and manganese (73% DV), and vitamin K (542% DV). Nattō contains some B vitamins and vitamin C in moderate amounts (table).

Appearance and consumption

''Nattō'' has a distinctive odor, somewhat akin to a pungent aged cheese. Stirring ''nattō'' produces many sticky strings. The dish is eaten cold with rice, mixed with the included soy sauce or karashi mustard if eaten from a commercially packaged ''nattō''. Other ingredients such as long onion or kimchi are often added.

''Nattō'' is frequently eaten as ''nattō'' ''gohan'' (''nattō'' on rice). ''Nattō'' is occasionally used in other foods, such as ''nattō'' sushi (nattōmaki), ''nattō'' toast, in miso soup, tamagoyaki, salad, as an ingredient in okonomiyaki, chahan, or even with spaghetti. Sometimes soybeans are crushed before fermenting.

Many find the taste unpleasant and smelly while others relish it as a delicacy. Nattō is more popular in some areas of Japan than in others. ''Nattō'' is known to be popular in the eastern Kantō region, but less popular in Kansai.

For those who dislike the smell and texture of natto, "dried natto" and "fried natto" were developed around 1990. The smell and stickiness are reduced, making it easier to eat for those who do not like conventional natto. Another type of fermented soybeans called ''mamenoka'' () has also been developed by improving the soybean and natto bacillus varieties to make it less sticky.

Production process

Commercial

''Nattō'' is made from soybeans, typically ''nattō'' soybeans. Smaller beans are preferred, as the fermentation process will be able to reach the center of the bean more easily. The beans are washed and soaked in water for 12 to 20 hours to hydrate them, and increase their size. Next, the soybeans are steamed for six hours, although a pressure cooker may be used to reduce the time. The cooked beans are mixed with the bacterium ''Bacillus subtilis'', known as ''nattō-kin'' in Japanese. From this point on, care must be taken to keep the ingredients away from impurities and other bacteria. The mixture is fermented at for up to 24 hours. Afterward, the ''nattō'' is cooled, then aged in a refrigerator for up to one week to allow the development of stringiness.

In ''nattō''-making facilities, these processing steps have to be done while avoiding incidents in which soybeans are touched by workers. Even though workers use ''B. subtilis natto'' as the starting culture, which can suppress some undesired bacterial growth, workers pay extra-close attention not to introduce skin flora onto soybeans.

Home

''Nattō'' continues to be a popular home fermentation activity with some families starting new batches daily. Home production was historically done using rice straw to maintain moisture and as insulation with placement in naturally warmer parts of the home or fermentation shed, but is now done with moist towels over glass pans or perforated plastic wrap on thermostat-controlled heating pads. At-home fermentation machines are also available but are rarely marketed specifically for ''nattō'', which is a less finicky culture capable of sustaining its own ideal temperature once it gets going.

End product

Mass-produced ''nattō'' is sold in small polystyrene containers. A typical package contains two, three, or occasionally four containers, each . One container typically complements a small bowl of rice.

''Nattō'' odor comes from diacetyl and pyrazines, but if it is allowed to ferment too long, then ammonia is released.

The fermenting of ''nattō'' develops glutamic acid, which is why it has an umami flavour.

Related products

Many countries around Asia also produce similar traditional soybean foods fermented with ''Bacillus'' bacteria, such as ''shuǐdòuchǐ'' (水豆豉) of China, '' cheonggukjang'' (청국장) of Korea, '' thua nao'' (ถั่วเน่า) of Thailand, '' kinema'' of Nepal and the Himalayan regions of West Bengal and Sikkim, '' tungrymbai'' of Meghalaya, ''hawaijaar'' of Manipur, ''bekang um'' of Mizoram, '' akhuni'' of Nagaland, and ''piak'' of Arunachal Pradesh, India.

Gallery

File:Natto mixed.jpg, ''Nattō'' being stirred with chopsticks
File:Natto gunkan maki by LWY in Fukuoka.jpg, ''Nattō gunkan maki'' (''Nattō'' sushi)
File:納豆卵かけご飯 07.jpg, ''Nattō'' served on white rice with raw egg
File:Natto, with welsh onion and karashi by yoppy.jpg, ''Nattō'' topped with karashi mustard and negi onion

See also

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* Cheonggukjang – Traditional Korean food made by fermenting soybeans.
* Other fermented soy foods include soy sauce, Japanese miso and fermented tofu.
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* Kinema traditional Nepalese food made from fermented soybean
* Nattokinase

References

{{DEFAULTSORT:Natto
Fermented soy-based foods
Japanese cuisine terms
Japanese inventions
Japanese cuisine
Buddhist cuisine
Articles containing video clips