Nattō

"natto" redirects here. For the alliance, see NATO.

Natto typically is eaten on rice

Nattō (なっとう or 納豆) is a traditional Japanese food made from soybeans fermented with Bacillus subtilis. It is popular especially as a breakfast food. As a rich source of protein, nattō and the soybean paste miso formed a vital source of nutrition in feudal Japan.^{[citation needed]} Nattō may be an acquired taste because of its powerful smell, strong flavor, and slimy texture. In Japan nattō is most popular in the eastern regions, including Kantō, Tōhoku, and Hokkaido.

History

Sources differ about the earliest origin of nattō. The materials and tools needed to produce nattō commonly have been available in Japan since ancient times; one source^{[citation needed]} puts the first use of nattō in the Jōmon period (10,000–300 BC). According to other sources^{[citation needed]} the product may have originated in China during the Zhou Dynasty (1134-246 BC). There is also the story about Minamoto no Yoshiie who was on a battle campaign in northeastern Japan between 1086 AD and 1088 AD when one day they 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. A third source places the origin of nattō more recently, in the Edo period (1603–1867).^{[citation needed]} It is even possible that the product was discovered independently at different times.

One significant change in the production of nattō happened in the Taishō period (1912–1926), when researchers discovered a way to produce a nattō starter culture containing Bacillus natto without the need for straw. This simplified production and permitted more consistent results.

Appearance and consumption

Opening and stirring a container of nattō

The first thing one notices after opening a pack of nattō is its distinctive smell, somewhat akin to a pungent cheese. Stirring the nattō produces lots of sticky strings. The nattō strings themselves are often described by the Japanese ideophone nebaneba, which roughly translates as 'viscid' or 'gooey'.^{[citation needed]} The flavor of nattō is nutty, savory, and slightly salty.^{[citation needed]}

Nattō commonly is eaten at breakfast to accompany rice, possibly with soy sauce, tsuyu broth, mustard, scallions, grated daikon, okra, or a raw egg.^{[citation needed]} In Hokkaidō and the northern Tōhoku region, some people dust nattō with sugar. Nattō frequently is used in other foods, such as nattō sushi, nattō toast, in miso soup, tamagoyaki, salad, as an ingredient in okonomiyaki, or even with spaghetti. A dried form of nattō, having little odor or sliminess, may be eaten as a nutritious snack.^{[citation needed]} There is even nattō ice cream. Sometimes soybeans are crushed and fermented. This is called 'hikiwari nattō'. It is a food that is easy to digest.^{[citation needed]}

The perceived flavor of nattō can differ greatly between people; some find it has a strong and cheesy taste and they may thus use it in small amounts to flavor rice or noodles, while others find it tastes bland and unremarkable, requiring the addition of flavoring condiments such as mustard and soy sauce. Many non-Japanese find the taste unpleasant and smelly, while others relish it as a delicacy. Some manufacturers produce an odorless or low-odor nattō.^{[citation needed]}

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. 236,000 tons of nattō are consumed in Japan each year.^{[citation needed]} A 2009 internet survey in Japan indicated 70.2% of respondents like Natto and 29.8% do not, but out of 29.8% who dislike Natto, about half of them eat natto for its health benefits.

Production process

Soybeans in a plantation

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 increase their size. Next, the soybeans are steamed for 6 hours, although a pressure cooker may be used to reduce the time. The beans are mixed with the bacterium Bacillus subtilis natto, known as nattō-kin in Japanese. From this point on, care must to be taken to keep the ingredients away from impurities and other bacteria. The mixture is fermented at 40 °C (104 °F) 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. During the aging, at a temperature of about 0 °C, the bacilli develop spores, and enzymatic peptidases break down the soybean protein into its constituent amino acids.^{[citation needed]}

In Natto making faculties, these processing steps have to be done by avoiding incidents which soy beans are touched by workers. Even though workers use Bacillus subtilis natto as the starting culture which can suppress some of other undesired bacterial growth, workers pay an extra- close- attention not to introduce skin flora onto soy beans.

Historically, nattō was made by storing the steamed soybeans in rice straw, which naturally contains B. subtilis natto. The soybeans were packed in straw and left to ferment. The fermentation was done while the beans were buried underground beneath a fire or stored in a warm place in the house, for example under the kotatsu.^{[citation needed]}

Regardless of the process, Japanese manufacturers need permission from the prefectural government, as required by food sanitation law.^{[citation needed]}

End product

Nattō is sold in small containers

Today's mass-produced nattō is sold in small polystyrene containers. A typical package contains two, three, or occasionally four containers, each 40 to 50 g. One container typically complements a small bowl of rice. It usually includes a small packet of soy sauce and another packet of karashi, a type of mustard. Other condiments to accompany the nattō, such as shiso, also are available.^{[citation needed]}

Mito City and Kumamoto Prefecture are major nattō-producing areas.^{[citation needed]}

Sometimes outside of Japan, frozen nattō is sold that must be thawed before consumption.^{[citation needed]}

To make nattō at home, you need a bacterial culture of B. subtilis. B. subtilis nattō is weak in lactic acid, so it is important to prevent lactic acid bacteria from breeding. Some B. subtilis nattō varieties that are more odorless are usually less active, raising the possibility that minor germs will breed. Bacteriophages are dangerous to B. subtilis. After a bacteriophage has infected a B. subtilis colony, minor germs may breed in the soybeans, particularly in boiled soybeans.^{[citation needed]}

Natto has a different nutritional makeup from when it was raw soy beans, losing Vitamin A, and other Vitamins and minerals compared to raw soy beans. However, calories in Natto are lower than in raw soy beans. Soy beans are highly nutritious, however the nutrition is packed in hard fiber. Natto has the benefit of nutritious soy and softer dietary fiber without too much sodium, which is present in high concentrations in other soy products like miso. Natto contains no cholesterol, almost no sodium, but is a significant source of iron, calcium, magnesium, protein, potassium, vitamin B6, B2, E, K2 and more. When Natto is mixed with egg and eaten with rice, Japanese call the dish a perfectly nutritious meal, covering all nutrition needs.

When Bacillus subtilis natto breaks up soy protein, the bacteria creates chains of polyglutamic acid, Gamma polyglutamic acid. The unique part of this polypeptide chain is that the peptide bond is between Nitrogen and R-group’s carboxyl acid.

Health Benefits

The Japanese media frequently claim, especially in television shows for health-concerned viewers, that nattō is health-enhancing and that these claims are backed by medical research.

One example is pyrazine: Pyrazine is a compound that, in addition to giving nattō its distinct smell, reduces the likelihood of blood clotting. It also contains a serine protease type enzyme called, nattokinase which also may reduce blood clotting both by direct fibrinolysis of clots, and inhibition of the plasma protein plasminogen activator inhibitor 1. This may help to avoid thrombosis, as for example in heart attacks, pulmonary embolism, or strokes.

An extract from nattō containing nattokinase is available as a dietary supplement. Studies have shown that oral administration of nattokinase in enteric capsules leads to a mild enhancement of fibrinolytic activity in rats and dogs. It is, therefore, plausible to hypothesize that nattokinase might reduce blood clots in humans—although clinical trials have not been conducted. Another study suggests that Fibrinolysis Accelerating Substance (FAS) in natto is the substance which initiates fibrinolysis of clots, which accelerates the activity of not only nattokinase, but urokinase.

A 2009 study in Taiwan indicated that the nattokinase in natto has the ability to degrade amyloid fibrils, suggesting that it might be a preventative or a treatment for amyloid-type diseases such as Alzheimer's.

Natto is rich in vitamin K. It contains large amounts of vitamin K₂, which is involved in the formation of calcium-binding groups in proteins, assisting the formation of bone and preventing osteoporosis. Vitamin K₁ is found naturally in leafy greens, seaweed, liver, and some vegetables, while vitamin K₂ (Menatetrenone) is found in fermented food products such as cheese, miso, and Nattō. Nattō has large amounts of vitamin K₂, approximately 870 micrograms per 100 grams of nattō.^{[citation needed]}

According to a study, fermented soybeans, such as nattō, contain vitamin PQQ, which is important for the skin. PQQ in human tissues is derived mainly from diet.

According to recent studies, polyamine suppresses excessive immune reactions, and nattō has a much larger amount of it than any other food. Dietary supplements containing the substances extracted from natto such as polyamine, nattokinase, FAS, and vitamin K₂ are available.

Nattō contains chemicals alleged to prevent cancer, for example, daidzein, genistein, isoflavone, phytoestrogen, and the chemical element selenium, however, most of these chemicals also may be found in other soybean products, and their effect on cancer prevention is uncertain.

Recent studies show nattō may have a cholesterol-lowering effect.

Nattō is said^{[citation needed]} to have an antibiotic effect, and its use as medicine against dysentery was researched by the Imperial Japanese Navy before World War II.

Nattō is claimed to prevent obesity^{[citation needed]}, possibly because of its low calorie content of approximately 90 calories per 7–8 grams of protein in an average serving. Unverified claims^{[citation needed]} include improved digestion, reduced effects of aging, and the reversal of hair loss in men due to its phytoestrogen content, which can affect testosterone associated with baldness. These conjectured physiological effects of eating natto are based on biochemically active contents of nattō, and have not been confirmed by human study.

Nattō is also sometimes used as an ingredient of pet food, and it is claimed that this improves the health of the pets.

Ecological use

Natto’s polyglutamic acid is useful as an organic polymer coagulant. Polyglutamic acid is useful in making organic and inexpensive water cleaner products, PGα21Ca, sold as a powder.

Similar foods

Many countries produce similar traditional soybean foods fermented with Bacillus subtilis, such as shuǐdòuchǐ (水豆豉) of China, cheonggukjang (청국장) of Korea, thuanao (ถั่วเน่า) of Thailand, kinema of Nepal and the Himalayan regions of West Bengal and Sikkim, hawaijaar of Manipur, akhuni of Nagaland, piak of Arunachal Pradesh, India. In addition certain West African bean products are fermented with the bacillus, including dawadawa, sumbala, and iru, made from néré seeds or soybeans, and ogiri, made from sesame or melon seeds.

Methods of eating nattō differs from region to region. Nattō is eaten with rice, with curry, Chinese noodles, Japanese style pasta, and tempura.^{[citation needed]}

Natto dishes

Salted nattō is a local dish in the Kouchi prefecture of Japan. Salt is sprinkled over nattō, and roasted nuka (powdered rice bran) is added in the pan. In the traditional recipe, the nattō soybeans are steamed with momigara (rice chaff).

Stamina nattō is nattō mixed with minced chicken, then stir-fried in sesame oil, ginger, garlic and Tabasco. It is served with the school lunch in the Tottori prefecture.

Nattō Ae is nattō mixed with cheese, soy sauce, parsley, and sugar. It is served with the school lunch in the city of Toyota in the Aichi prefecture of Japan.

Nattō-jiru is a kind of miso soup, which consists of nattō and vegetables and popular in the Tohoku area.

Nattō-maki is a kind of sushi roll.

Soboro-nattō is a speciality in Ibaraki, mixing nattō and kiriboshi-daikon (cut and dried daikon raddish), seasoned with soy sauce.

Hoshi-nattō (sun dried nattō) is an Ibaraki speciality which can be stored for long time. This is eaten as is, or eaten as Chazuke. Originally, hoshi-nattō is a preserved food. It is often eaten by Japanese when away from Japan.

Age-nattō (fried nattō) looks simillar to hoshi-nattō. This product is removed the stickiness by deep-frying and is seasoned with soy sauce and/or salt. The peculiar smell is lessened by this process. This is eaten as is or as a relish with alcohol.

Sakura-nattō is a popular dish in Kumamoto prefecture, which mixes nattō and raw horse meat (sakura-niku, lit.cherry meat) seasoned with soy sauce.

Gallery

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  A nattō bean-size legend using beans before fermentation in a supermarket

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  Natto being stirred with chopsticks

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  Nattō gunkan maki (Nattō sushi)

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  Nattō wrapped in rice straw, old style nattō package

See also

• Amanattō – is not nattō, but rather, beans sweetened with sugar
• Fermented bean paste
• Japanese cuisine – Other fermented soy foods include soy sauce, Japanese miso, Chinese dòuchǐ (fermented black soybeans), fermented tofu and (a subcategory) chòu dòufu (stinky tofu), Korean doenjang, Meju, and cheonggukjang, Nepalese kinema, and Indonesian tempeh and oncom.
• List of fermented soy products

External links

• Natto Land-How to eat natto with instruction for making natto at home
• Health benefits of eating natto-Article about dieting eating fermented soybeans