Editor’s note: The theme of Gohan Lab is to help people make simple, tasty “gohan” (meals).

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Why does tofu set after “nigari” (bittern), a salty brine, is added?

Explaining exactly what happens during the chemical reaction may be a little esoteric. But long before how it worked ever became clear, our ancestors came up with a way to effectively consume the protein from soybeans, which is otherwise difficult to digest.

Their efforts to improve the texture by using a generous amount of water were possible in a land where water is plentiful.

In the last entry in our series focusing on the appeal of tofu, we introduce “iri-dofu,” or sauteed tofu.

We combine a light-tasting tofu with umami-rich “chikuwa” (cooked fish paste) and shiitake mushrooms--flavors that we will bring together in the end with an egg. The dish is nutritionally balanced and packed with wisdom.

Preparing it requires a subtle approach, otherwise the tofu could break up into pieces that are too small, or it could become watery.

But there are two keys to solving these problems. First of all, cook the other ingredients first, until tender, and then add the tofu later. Taking into account that there is already water in the tofu, only use a tiny amount of simmering liquid. Since the tofu will release water, removing water from it beforehand is not necessary.

HOMEGROWN SOYBEANS INCREASINGLY POPULAR

We are seeing more tofu with labels listing “homegrown soybeans” as an ingredient. According to data collected by the agriculture ministry, sales of homegrown tofu have grown from 8 percent in 2007 to about 16 to 17 percent in recent years.

Of the edible soybeans that are made into tofu and natto (fermented soybeans), about 20 percent are grown in Japan. The plant is susceptible to changes in the weather and a stable supply is said to be a challenge. But the government aims to increase the yield in 2030 to 1.6 times that of 2018.

BASIC COOKING METHOD

(Supervised by Akiko Watanabe in the cooking aspect and Midori Kasai in the cookery science aspect)

* Ingredients (Serve three)

300 grams firm “momen” tofu, 50 grams carrot, 2 shiitake mushrooms, 1 small chikuwa, 2 stalks green onion (hosonegi type), 1 egg, 1 Tbsp oil, 100 ml dashi stock, 1 Tbsp sugar, 1 Tbsp soy sauce, 1/6 tsp salt

About 175 kcal and 1.7 grams salt per portion

1. Break tofu up by hand into pieces that are about 2 cm on a side. Spread them out on flat sieve (PHOTO A).

2. Peel carrot and slice into fine quarter sectors. Remove stem from shiitake and finely slice cap. Remove hard end from stem and slice lengthwise. Cut chikuwa into thin round slices. Finely chop green onion. Break and mix egg.

3. Heat oil in frying pan, add carrot and stir-fry over low heat. When it turns transparent, add shiitake. Once it is coated with oil, add dashi stock and chikuwa. Place lid and simmer over low heat for 4 to 5 minutes until almost no liquid remains.

4. Add tofu and when water is released, add sugar, soy sauce and salt. Raise to medium heat and reduce while mixing (PHOTO B). Pour egg in circular motion and cook (PHOTO C). Add green onion and turn off heat.

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Akiko Watanabe is a cooking expert specializing in Japanese cuisine.
Midori Kasai is a professor at Ochanomizu University and former chairwoman of the Japan Society of Cookery Science.

ARRANGED VERSION

Simmered meat and tofu (“Niku-dofu”)

The ingredients for two servings are 300 grams silken tofu, 100 grams “komagire-niku” (scraps of beef slices) and 1/2 green onion (naganegi type). Cut tofu into eight equal parts, place on a sieve to drain water. Cut green onion at an angle into 5-mm-thick slices. Add 100 ml dashi stock, 1 and 1/2 Tbsp of sweet mirin sake and the same amount of soy sauce, 1/2 Tbsp sugar to frying pan, and place on medium heat. When it comes to a boil, add beef by spreading pieces, lower heat and skim off foam. Add tofu and green onion and simmer over low heat for 2 to 3 minutes.

COOKERY SCIENCE

Soymilk sets into solid tofu by the action of coagulants. Soymilk protein will stick together because of the coagulant, first forming a network and then setting by enclosing the water in the network. The strength of the bond depends on the type of coagulant and concentration of the protein, among other factors. Whether the process includes a step for removing the water content will affect the tofu’s hardness and texture.

SEEKING OPINIONS AND IDEAS

We are asking our readers to tell us about past recipes that proved useful and themes you would like us to focus on in the future.

Please send your email to seikatsu@asahi.com or fax to (03) 5540-7354 or write to Gohan Lab Desk, Culture and Lifestyle News Section, The Asahi Shimbun, Tokyo 104-8011.

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From The Asahi Shimbun’s Gohan Lab column