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Homemade Natto

People are split to two groups, those who love natto and those who hate. Even if you belong to the latter, the benefits of natto are worth to read. We cite the following two excerpts from Internet.

The enzyme known as nattokinarse found in the sticky part of Natto (fermented soybeans) has blood cleaning properties and can reduce the thick blood that builds up in veins, preventing such incidences as artery hardening and memory loss. Nattokinase helps the processes of digestion of protein, fat, fiber and starch. Consequently, natto is known as "Edible Stomach Medicine". The unique smell of natto is one part of its characters, and even in this smell are special substances that help the flow of blood in the body.

http://www.optic.or.jp/com/hiruzen_shokuhin/hiruzen_shokuhin_e.html

Figure 1 Homemade natto

In the old days, people knew from experience that natto was good for them, but it took modern science to discover exactly why. In addition to all the fine properties originally found in soybeans, natto fermentation doubles the amount of Vitamin-B2, Vitamin-B12 and Vitamine-E. It also produces Vitamin-K, making Natto especially good for preventing osteoporosis. During fermentation, nattokin also produces a wide variety of enzymes.

http://www.asahi-net.or.jp/~by7m-kknm/nattou-e.htm

According to the research at The National Cancer Research Center in Japan, the death rate of the people who eat natto is 20% less than those who do not eat natto. A research at Oxford University reveals that the risk of death by heart diseases is decreased by 18%, and that the risk of death by brain stroke is reduced by 28%.

The medicinal benefits are enhanced by eating egg together with natto because the protein in egg and that in natto augment each other. The same effects are also realized by eating shirasu (tiny white fishes) together with natto, although shirasu may be difficult to obtain outside Japan. In such cases, dried tiny anchovies available from Amazon.com are as good.

Figure 2 Tiny fishes, Shirasu

Nattokin or Natto Starter

Nattokin means natto spores, or natto starter. A few brands are available as illustrated in the following figures.

Figure 3 Nattokin 3g to make 30Kg of natto, available at Etsy.com

Figure 4 Nattokin 3g to make 30kg of natto, available at Amazon.com

One scoop of nattokin (1 micro-spoon full) weighs about 0.1g, which is enough to make 1 Kg natto. If you start with 1 cup of dry soybeans, it will make about 400g of natto because dry soy beans absorb water. Therefore, the amount of nattokin is about ½ scoop with the micro-spoon. Measuring a small amount of nattokin less than 0.1 g is very difficult, so instructions that comes with nattokin use very obscure expressions, such as “one dash of nattokin is to be used for one time of making natto”.

How to Make Natto

Materials

1 cup dry soybeans (170g)

One dash (or ½ - 1 micro-spoon) of nattokin

Equipment

Flat plastic food container, 8"x12", with a lid, or a few ½ Lb plastic containers

Pressure cooker

Soak soybeans in water for 8 hours or overnight. A pressure cooker is recommended in cooking soybeans. Place the soaked soybeans in the pressure cooker. Add water to cover the soybeans. Heat the pressure cooker first without placing the lid. In five to ten minutes, as boiling starts, much foam starts floating on the top. Remove the foam with a paddle, and then close the lid to pressurize. Cook under pressure for 7-8 minutes. The cooked soybeans should not be too soft because they become further softer through fermentation. Cool it down to 104F (40C). Drain completely in a colander.

Dissolve nattokin in a teaspoon of warm water. Sprinkle the nattokin water over the soybeans, and stir by a wooden spatula so the nattokin is spread in soybeans as evenly as possible.

Figure 5 Inoculated soybeans in plastic fermentation containers

Place the inoculated soybeans in plastic containers for fermentation. Do not overload the plastic fermentation vessels with soybeans. Three layers of soybeans are a limit because too much soybeans prevent air from reaching the soybeans. Use multiple fermentation vessels if needed.

Put a cover over each fermentation vessel and keep it at 95 - 104F (35 - 40C) for 24 hours. To maintain the temperature, a picnic icebox with bottles filled with hot water may be used. A better way is to use a heat pad controlled by a temperature regulator.

Another way is to use a yogurt maker, as illustrated in Figure 6 named “DiDimo”, available at Amazon.com for $36. DiDimo has multiple capabilities. It is sold as yogurt maker, but is capable to ferment natto and rice wine. In using this device for natto making, set the dial to “natto”, and follow the directions written in the manual. Do not stack too much soybeans in the inner crock. The maximum is three layers of cooked soybeans. As the author measured the temperature when natto making was selected, the temperature reached a maximum of 44 C. The author trusts this device, however.

Figure 6 An example of yogurt maker “DiDimo”.

Natto fermentation can be started using a small amount of commercially available natto as seed. However, the quality becomes far better if nattokin is used as starter. Indeed, if a commercially available natto is used as starter, more or less ammonia smell is felt in natto, probably because the bacilli are not pure. One method to improve is to reduce the time length of fermentation to 12 hours from 24 hours. In this case natto is less fermented. On the other hand the ammonia smell is hardly a problem when nattokin is used as starter.

How to Eat Natto

The standard way to eat natto in Japan: Usually green onions, mustard and soy sauce are added as condiments. Chopped green onions and mustard reduce the natto smell considerably. Mixing natto 424 times is said to mostly eliminate its sliminess (don't ask why 424). Wasabi may be used instead of mustard. Eat with white rice. However, it is cautioned not to heat natto. Putting natto to very hot rice is not good either, because heat kills the health benefits of natto. The amount of natto consumed in a day should not exceed 50 grams (one small pack). Eating natto has an effect of diet and reduction of body weight, but exceeding the limit rather increases the body weight.

Natto Mayo Spread: If you just stir in mayonnaise and a few drops of soy sauce to natto, spread it on bread. Especially when made as a sandwich, the smell and sliminess are hardly noticed, making this a recommended recipe.

Apple Natto: Finely slice apple and mix with natto. Soy sauce and mayonnaise may be added. Sour apples are the best for this recipe.

California Natto: Mix avocado and natto, and add soy sauce for taste. This is recommended for people who like a lingering taste. However, the avocado turns black, so do it just before eating.

Adding vinegar or lemon juice: If ammonia small bothers, mixing a small amount of vinegar or lemon juice just before eating eliminates ammonia smell.

Health Benefits of Natto

According to National Cancer Research Center in Japan, its research on 93,000 people of 40 to 60 years old indicated that the people who eat natto has a lower death rate than those who do not eat natto. The reasons are attributed to that (1) natto contains isoflabon, (2) natto is rich in fiber, (3) nattokinase contained in natto tends to lower viscosity of blood.

In recent years natto was found to kill the corona viruses. A corona virus contains four major proteins, S-protein, E-protein, M-protein and N-protein, referring to spike protein, envelope protein, nucleocapsid protein, myeloma protein, respectively. The spikes on the outer surface of a corona virus contain the S-protein.

The S-protein combines with human cell acceptors and become a virus manufacturing factory. Then, human capillary blood vessels are damaged because when this happens on the inner surface of the capillary blood vessels, the blood vessels bleed and are thrombosed, causing massive inflammation. Thus, the S-protein is very toxic and said to be killers in blood. Recent research found that nattokinase in the blood melts away the S-protein and destroys corona viruses.