大豆 / Daizu (Soybeans) - The power of the 'Great Bean'-
Tōfu. Miso. Shōyu. These three Japanese ingredients are commonplace, even on dining tables in Australian homes and all three are produced from soybeans (known as ‘daizu’ in Japanese). Daizu are an essential part of Japanese diet, but in recent years they have begun to play a part in other parts of our lives. Good for your health and kind to the environment; we investigated the power of the ‘Great Bean’.
Source: Hokkaido Prefecture Central Agricultural Laboratory Professor Souma’s Produce EncyclopaediaRich in protein, daizu are also known as ‘meat of the fields’. One hundred grams of daizu contains more protein (33~35g*) than the same amount of whole raw egg (12.3g*) and beef (18~21g*), and it was the precious source of protein for Japanese people in the past who didn’t eat much meat. In modern times we are becoming more and more health conscious and daizu, which are low in calories but full of protein, fibre and nutritional value, are gaining attention as healthy food not only in Japan, but the whole world.
The History of Daizu
It is believed that daizu were originally cultivated in ancient China and during the Jōmon (14,000~300 BC) and Yayoi (300 BC ~ 250 AD) periods, more than 2000 years ago, came to Japan through the Korean Peninsula. During the Nara period (710~794 AD), Buddhism brought with it the techniques to make processed foods like miso and soy sauce, and as it forbade the eating of meat, the cultivation of the important alternative source of protein, daizu, became increasingly widespread.
With each new era, food processing technologies also improved and in addition to miso and shōyu (Japanese soy sauce), foods like nattō (fermented soybeans), tōfu, kinako (powdered dry soybeans) and yuba (also known as tōfu skin; a by-product of tōfu) were made and have become a very important source of protein for modern-day Japanese people.
Types of Daizu
There are many types of daizu varying in colour and shape, however the beans that are used to make things like miso, soy sauce, nattō and tōfu are most commonly Kidaizu (yellow soybeans). The boiled beans used in Osechi cooking (foods eaten over the New Year period) are Kuromame (black soybeans) and those used to make kinako and regular boiled beans are Aodaizu (blue soybeans).
Foods made from Daizu
Miso is made by adding kōji (grains fermented in kōji bacteria) and salt to steamed daizu and allowing it to ferment. Water soluble miso was made during the Kamakura period (1185~1333 AD) which led to the creation of miso soup (known as miso-shiru). For soldiers in the Sengoku period (1467~1573 AD), it was a convenient source of nutrients as it kept well. The salt content in miso soup which tends to play on our minds is cancelled out by other ingredients like spinach (full of potassium), potatoes and seaweed (high in fibre). The wakame (soft seaweed) in miso soup is especially useful for absorbing the excess salt and discharging it from our bodies. In addition, experimental evidence shows that people who drink miso soup are less likely to get stomach related illnesses such as stomach ulcers and stomach cancers than those who don’t.
●Shōyu (Japanese soy sauce)
Shōyu is a seasoning made from daizu and wheat kōji which has had salt water added and left to ferment (recently shōyu made without wheat has also been developed). The protein from the daizu is broken down by the kōji fungus producing the amino acids which give shōyu its rich flavour. Its unique flavour comes mainly from the daizu‘s protein; the aroma comes from the wheat’s starches; the microorganisms in the kōji fungus work to bring out each quality of shōyu. There are many types of shōyu ranging from the common Koikuchi (dark soy sauce), the lighter coloured and flavoured Usukuchi, and the thicker type known as Tamari (often used with sashimi), through to Saishikomi (rich in colour, flavour and aroma) and the sweeter Shiro.
Nattō is made by adding nattō bacteria (a type of bacillus subtilis) to steamed daizu and allowing it to ferment. The stickiness in nattō comes from the glutamine which is made when the nattō bacteria breaks down the daizu’s protein. The nutritional value of nattō is very high; it not only has high quality proteins, saponins (a class of chemical compounds), vitamins and minerals, it is also abundant in vitamin K which is necessary for the formation of bones. In addition to this, nattō has many beneficial active ingredients, such as nattō kinase (a type of enzyme produced by the nattō bacteria), which work together to improve the function of the intestines and immune system. They also have anti-bacterial properties, reduce the risks of cancer, dissolve blood clots, lower blood pressure and various other effects.
●Tōnyū (Soy milk)
Daizu that have been soaked in water are crushed and boiled and the mixture is then strained to produce tōnyū. If you add nigari (a by-product of the process of making salt from seawater consisting mostly of magnesium chloride and calcium chloride) to tōnyū it becomes tōfu. Tōnyū is recognised for reducing hypercholesterolemia (high levels of cholesterol in the blood), improving intestinal conditions, as well as replenishing iron levels. People involved in making tōfu from tōnyū are known to have beautiful pale hands and this has led to the popularity of cosmetics such as skin lotions, soaps, face packs which use the whitening agents of tōnyū.
Tōfu is made using nigari or other coagulants to set tōnyū. Kinugoshi-tōfu (silken or soft tōfu) is made by pouring the tōnyū and setting agent mixture into a mould and simply allowing it to set. Tōfu which has been pressed and had much of its moisture drained off is called momen-dōfu (firm tōfu). As the manufacturing process takes away much of the extra dietary fibre of daizu, tōfu is more efficiently digested meaning that there is no wastage of nutrients. Further processing of tōfu creates many other types, such as kōyadōfu (freeze-dried, spongy tōfu), abura-age (thinly sliced, deep-fried tōfu)and assuage (deep-fried tōfu). Low in calories and high in protein, tōfu is an excellent health food which is being consumed more and more, not only in Japan, but all over the world.
The Diligence of Daizu
Reduce cholesterol and protect your liver!
The abundance of linoleic acid in daizu prevents high cholesterol build-up in the blood as well as the hardening of arteries. The glycine in daizu also helps to reduce cholesterol levels while the phospholipids they contain promote the burning of fat which in turn controls the build-up of fat in the liver. Daizu contain saponins which also help to discharge fats, sugars and other harmful substances, along with vitamin B complex which has dietary properties assisting in the burning of fats and starches. On top of all that, daizu are said to prevent cell aging and cancer. Daizu really is the ‘Great Bean’!
For beauty and health!
Daizu contain a great amount of isoflavones which act in a similar way to female hormones helping to reduce menopausal disorders, prevent and treat osteoporosis. Also useful as beauty treatments, improving skin whitening and moisture, daizu are a girl’s best friend.
They are even used in printing!
Daizu are also used to make soy-based ink for printing. Compared to traditional petroleum-based inks, they not only reduce the consumption of oil resources, they also make it easier to recycle the paper as the ink can be removed with less damage to the paper’s fibres. Being produced from biodegradable vegetable oils, the disposal of soy-based inks is far more environmentally friendly. Originally invented in America, over 90% of the country’s daily newspapers are printed using soy-based inks according to the American Soybean Association.
Here are some ways to ‘Westernise’ typical daizu foods!
An easy treat; spread a little mayonnaise on your toast and simply put some nattōon top. If you sprinkle some roasted sesame seeds on top you not only add a great aroma, but you also double the effects of improving blood circulation. Even when you don’t have any rice you can easily and deliciously get the benefits of ‘daizu power’ with nattō. If you prefer you don’t have to toast the bread, just have it as it is. It is an unexpected combination, but give it a try. There are even a lot of people in Japan giving it a go...
The balance of hot tōfu and cheese is exquisite.
(Recipe for 2 people) ①Slice and sauté half an onion. ②Sprinkle over 1 tablespoon of flour and fry until it is no longer powdery then add 200cc of milk. ③Continue to stir it over a medium flame until it thickens and then add some tōfu (lightly broken up with your hands), salt, pepper, and a teaspoon of stock powder. ④Place the mixture into an oven-proof dish, sprinkle some cheese on top and bake it in a 180 oven for 10 minutes. Top it with chopped negi (spring onion) and katsuobushi (shredded dried bonito) to taste.
Get healthy with daizu!
Photography assistance: LITTLE TOKYO