A traditional Japanese food, natto has been in use since the ancient times. This food is prepared from soybeans. To prepare natto, you need to soak and ferment soybeans, which become somewhat sticky producing a squashy or web effect between the soybeans. Usually natto acquires the taste of the other substances it is cooked with. However, the fermenting process imparts as potent smell to natto and some people who are not accustomed to this dish may find the smell disagreeable. Moreover, consumption of natto may often lead to bad breath. Nevertheless, this problem can be overcome by brushing your teeth thoroughly.
Natto is very popular in some regions of Japan. Natto may be consumed in the form of a breakfast food, generally added with some sugar. Alternatively, this fermented soybean food may also be served along with rice. Some people also like to have natto and rice with sauces. They may use a variety of sauces to the food, including soy sauce and hot mustards and top it with grated radishes or quail eggs. Natto is a reasonably nourishing food and contains very few calories. One serving of natto provides with roughly 7 grams to 8 grams of protein and just 90 calories.
The Japanese also like natto because it contains elevated levels of vitamin K, in addition to loads of antioxidants, especially the trace mineral selenium. In addition, natto also encloses a type of protein known as nattokinase, which many believe is a natural anti-coagulant. Since this food is prepared by fermenting soybeans, it grows bacteria and is also a probiotic food.
In fact, the traditional process of making natto is more than 3,000 years old and, according to some food historians, it may have been first prepared some 10,000 years back. Some people are of the view that this food actually has its origin in China, but currently natto is believed to be mainly a Japanese food. In fact, there are several stories about the origin of natto and one of them suggests that this food may have been discovered by some soldiers (see below) accidentally when they were in a hurry and mistakenly packed some leftover cooked soybeans, which were not opened for many days, resulting to its fermentation.
People generally do not prepare natto at home, but purchase most of it prepared and ready to eat. Normally, natto is made by adding the bacterium Bacillus subtilis to soybeans to initiate the fermentation process. Earlier, this bacterium was called Bacillus natto. Fermentation of the soybeans makes them sticky and imparts a strong smell to the food.
Usually, most people who take this food for the first time find the flavour of natto to be somewhat nutty as well as sharp. This food actually tastes better than it smells. There are many who also think that natto is bland and needs to be taken after additional flavoring. People who do not want to eat natto owing to its strong smell should know that a number of companies have now produced natto with a less strong smell and they may find these products more edible.
Although natto is a popular food in Japan, not all people in this island nation prefer it. In fact, natto is more popular in the eastern regions of Japan. Moreover, natto is not readily available outside Japan. However, sometimes you may find this food in the frozen section of some markets in other Asian countries. Alternatively, occasionally natto is also available in the form of natto ice cream or dry natto, which is consumed in the same way you eat chips or nuts. A similar dish is available in Korea, which also includes fermented soybeans and is locally called cheongguikjang. People in China also make a dish containing fermented black bean and it is known as douchi.
Natto is prepared from soybeans, usually natto soybeans. Generally, people prefer smaller beans to make natto, because when these beans are fermented, the inside of the bean is fermented easily. Before making natto, the beans are washed meticulously and immersed in water for anything between 12 hours and 20 hours to allow them to enlarge in size. Subsequently, they are steamed for about 6 hours. However, you may use a pressure cooker to steam the soybeans as it will reduce the time greatly. Bacillus subtilis, called natto-kin in Japanese is then mixed with the steamed soybeans.
Once the bacteria are mixed with steamed soybeans, one should be careful to keep the ingredients protected from any impurity as well as other bacteria. The ingredients are usually fermented at temperatures around 40�C (104�F) for a maximum period of 24 hours. Subsequently, the fermented product is cooled and stored in a refrigerator to facilitate it to age for about a week. During this period, the natto develops its stringiness.
In facilities where natto is made, the above mentioned processing steps need to be undertaken to avoid even the workers touching the food. While the workers at the facility use Bacillus subtilis natto at the beginning of the culture to restrain any unwanted bacterial growth, they have to be additionally careful not to allow their skin flora to come in contact with the soybeans.
If you want to prepare natto at home, you need a bacterial culture of Bacillus subtilis. Since Bacillus subtilis natto becomes weak in lactic acid, it is very important to thwart the breeding of any lactic acid bacteria. There are a number of B. subtilis natto varieties and some of them do not impart strong smells. Generally, these varieties of the bacteria are not very active; as a result they increase the chances of minor germs being bred. In fact, bacteriophages are risky for Bacillus subtilis.
Traditionally, natto was prepared by accumulating the steamed soybeans in hay or rice straw. B. subtilis natto occurs naturally in rice straw. In fact, earlier, people packed soybeans in straw for fermentation.
Different sources provide dissimilar information regarding origin of natto. In fact, the ingredients as well as tools that are commonly used in making natto existed in Japan since the earliest times. According to one story, Minamoto no Yoshiie ventured out in a battle campaign in the northern regions of Japan between the period 1086 AD and 1088 AD. One day they were attacked by the enemy while they were boiling soybeans to feed their horses. In a hurry, they packed the steamed soybeans in straw bags and did not open them for few days. By the time, they opened the straw bags, the soybeans had become fermented and the soldiers consumed them anyway. Incidentally, they took a liking for the flavour of these fermented beans and offered some of it to Yoshiie and even he liked their taste. While this story may be true, it is even possible that natto was actually discovered by different people separately at various times.
During the Taish? period (1912-1926), there was a noteworthy change in production of natto. It was during this time that researchers discovered a new method of producing a natto starter culture that contained Bacillus subtilis even without the need for packing the steamed soybeans in rice straw. This was a more simple process to make natto and the results were relatively more consistent too.
There are very few foods that enclose vitamin K1 (usually present in green leafy vegetables) as well as vitamin K2 (only produced by bacteria). However, natto is among the rare exception, as a serving of 100 grams of this food encloses 23.1 micrograms of these vital nutrients, which is roughly 29 percent of an adult human being's recommended daily intake (RDI). Our body requires vitamin K to regulate clotting of blood as well as to put off bone loss. In addition, this important vitamin is also necessary to prevent calcification of the arteries. A deficit of vitamin K in our body may cause osteoporosis, augmented bleeding, counting menstrual bleeding, as well as deferred response to bruises and wounds.
It has been established that natto is an excellent probiotic source. There are several reasons why this food is healthy. A major reason is that natto is made from fermented soybeans. Usually, processed and non-fermented soybeans lead to a variety of health problems, including hormone and thyroid dysfunctions. On the other hand, consuming fermented soybeans do not lead to such health problems. This is because the fermentation process helps to do away with these issues. Aside from this, when soybeans are fermented, they contain plenty of helpful bacterial cultures that not only support our digestive system, but also works as a natural laxative. Therefore, natto is beneficial for people who are suffering from constipation.
Natto contains elevated levels of vitamin C. A 100-gram serving of natto contains 13 mg of this vital vitamin, which is about 22 percent of an adult human being's recommended daily intake or RDI. It has been proven that vitamin C is amongst the most potent antioxidants available today. In addition to providing us protection against damages caused by free radicals, which may result in development of cancer and various degenerative diseases like macular degeneration and cystic fibrosis, this vitamin also helps to perk up our immune system.
In addition, natto is also beneficial for people struggling to lose weight, as it is low in calorie content. A serving of 100 grams natto supplies the body with just 212 calories and a modest five grams of fiber. The dietary fiber contained by this fermented food gives us a sense of fullness after consuming it. As a result, natto is an excellent food for breakfast, especially for people who are keen to shed some additional flab. One such serving of natto also provides us with 11 grams of fat, which is considered to be somewhat high. In fact, these saturated fats are beneficial for the body, which requires them to generate energy.
Generally, vegans and vegetarians love to eat natto because this fermented food supplies them with several nutrients that are usually found in meat products. In addition, it also provides them with the much-needed protein and the essential mineral iron. Natto contains the entire eight essential amino acids, in addition to 8.6 mg iron, which is 48 percent of an adult human being's RDI. Our body requires protein for building cells and muscles, while iron is essential for transporting oxygen from the lungs to the various parts of our body.
Natto is also very helpful for the health of our teeth and bones. A serving of 100 grams of this fermented food contains roughly 217 mg of calcium, which is about 22 percent of an individual's RDI, in addition to 115 mg of magnesium, approximately 29 percent of one's RDI. While most of us are aware that calcium is essential for strong teeth and bones, many are not aware of the fact that we also require magnesium to help the body assimilate calcium from foods and supplements. As natto contains adequate amounts of both calcium and magnesium, it is considered to be an ideal food for developing strong bones and teeth. Regular consumption of natto helps to protect us against bone-related problems like arthritis, gout and osteoporosis.
This fermented soybean food also provides us with dietary fiber, linoleic acid and lecithin - all these are helpful in cleansing the blood and boosting the digestive process. Aside from this, natto is an excellent source of a nutrient called vitamin PQQ. This vitamin is not very well known, but it is necessary to sustain the health of our skin. Hence, it is necessary to obtain adequate amounts of this vitamin, mostly from our diet. Fortunately enough, natto contains reasonable amounts of vitamin PQQ.
Natto also contains modest quantities of B vitamins, including folate, thiamin, pantothenic acid, and riboflavin. It also provides us with vitamin B6 and vitamin B12, which facilitate metabolism inside the cells, and some amounts of omega-3 as well as omega-6 fatty acids. These fatty acids help to improve the brain's functioning. Natto also contains a number of trace minerals like copper, potassium, manganese, phosphorus and zinc. The glycemic load score of a serving of 100 grams of this fermented food is estimated to be five. In other words, it has very insignificant impact on the levels of blood sugar and, hence, natto is also suitable for people with diabetes.