"Fu" refers to a processed food made with wheat gluten being the main ingredient. Gluten is a type of protein contained in the water and wheat flour mixture.
Fu are available in various forms including the chewy nama-fu (fresh gluten cakes), the crisp yaki-fu (toasted gluten cakes) and age-fu (deep-fat fried gluten cakes) used in Chinese cooking. They are used in simmered dishes and soups. They are often used in various nabemono (stew, food cooked in a pot) such as sukiyaki and also in fried dishes in Okinawa cuisine.
The major production centers of fu in Japan are as follows:
Nama-fu and kazari-fu (decorative gluten cakes) are produced in Kyoto City and Kanazawa City. Yaki-fu is produced in various regions including the Iwafune district of Murakami City, Niigata Prefecture, Yamagata Prefecture and Okinawa Prefecture. Age-fu is made in Miyagi Prefecture.
In the People's Republic of China, Wuxi City, Jiangsu Province, is known as a production center of age-fu that are often used in simmered dishes of Shanghai cuisine. Additionally, there are some processed gluten cake products such as 'Mian Jin Sai Rou' which is gluten cakes with stuffing made of ground pork and other ingredients. Fu are also used in the Buddhist cuisine (in both Japan and China) and as ingredients for meat-substitute products for vegetarians in North America and Europe who do not eat meat for health or religious reasons. Tofurkey is available as a substitute for turkeys that are commonly served for Thanksgiving dinner.
Nama-fu and yaki-fu are sometimes used to make confectioneries in addition to being used in cooking. They fill nama-fu with red bean jam to make fu-manju pastries while they add food colorings and sugar to the dough of yaki-fu to make confectioneries such as fugashi. There is fu karinto sweetened with black sugar to simulate the taste of karinto (dough cut into sticks, deep-fat fried and sweetened).
Add brine to flour and knead the mixture to make dough. When the dough becomes sticky, transfer it to a cloth bag. Submerge the cloth bag in water and continue kneading the dough.
When starch in the dough has flowed out into the water, the remaining gluten is steamed to make nama-fu (or mochi-fu).
Knead together the above gluten, wheat flour, baking powder and glutinous rice flour and toast this dough to make yaki-fu.
Age-fu are made by deep-fat frying nama-fu.
Nama-fu are available in various flavors and colors that are made by adding other materials such as sesame seeds, mugwort leaves and safflower.
Additionally, starch discharged from the dough in this process is collected and dried to make shofu which becomes an ingredient of confectioneries.
Fu of various shapes
Ita-fu (gluten sheets)
As to Ita-fu, those formed into sheets and toasted, 'Shonai-fu' (fu of the Shonai district) in Shonai Town, Yamagata Prefecture are well known.
Manju-fu (gluten cakes in the manju shape - also known as Iwafune-fu). They are manju-shaped.
It is believed that the Iwafune district of Murakami City, Niigata Prefecture is the birthplace of manju-shaped fu, known as 'Iwafune-fu.'
These are made in the Kaetsu district.
Tsubushi-fu (flattened gluten cakes)
These are made by steaming the manju-fu and pressing them into the shape of discs when soft. They have high density.
Kuruma-bu (wheel-shaped gluten cakes)
The process of making kuruma-bu is similar to that of chikuwa, fish sausage, whereby aluminum posts are coated with fresh gluten dough that are roasted over an open fire. The above process is repeated a few times to form layers of roasted gluten cake. This is an essential ingredient for Okinawa cooking.
Oshi-fu (pressed, wheel-shaped gluten cakes)
It is made by pressing kuruma-bu like spring rolls. They are made in some areas including Yamagata Prefecture.
Age-fu is made by deep-fat frying nama-fu that has been formed into small balls in oils such as canola oil. When frying in hot oil, they develop air bubbles and expand into balls of about 6 cm in diameterwhich is the characteristic of age-fu of Wuxi City, China.
Those referred to as abura-fu are age-fu that have been formed into sticks. It is a traditional foodstuff of the Tome region of Miyagi Prefecture.
When used in soup, there is no need to develop abura-fu by soaking in water. Abura-fu can be cut into bite size pieces and added to simmered dishes to lend a rich flavor. When used in cooking with small amount of liquids, abura-fu has to be developed by soaking in water.
Kazari-fu are gluten cakes formed into various shapes such as flowers and traditional Japanese handballs that are also dyed in attractive colors with food colorings. Among various types of kazari-fu, 'Kyokomachi-fu' and 'Hana-fu' (flower-shaped fu) of Kyoto and 'Kaga kazari-fu' (decorative fu of the Kaga region) are well known.
Kaku-fu (rectangular gluten cakes)
Kaku-fu are those that are formed into a board shape by using bamboo mats and steamed. They have a corrugated surface. Kaku-fu is mainly produced around Nagoya City and is a popular food that is commonly available at supermarkets in the area. The main ingredients of kaku-fu are gluten and wheat flour.
Anpei-fu (round-shaped fu)
Anpei-fu is round yaki-fu that is produced in Yamaguchi Prefecture. Gluten and wheat flour are the ingredients of Anpei-fu. They look like cream puffs.
In old China, fu was referred to as mian jin (gluten) and was mentioned in "Meng Xi Bi Tan" (Dream Stream Essays) which was written during the Sung Dynasty era.
In Japan, the kanji representing 'fu' means rice bran and that character was used for mian jin which is a processed food made from rice bran later on ("Honcho shokkan" [Mirror of food in our country])
Additionally, since wheat came from China, it was also referred to as Karako (Chinese flour). During the Kamakura period, there were Kugonin (Karako kugonin) who paid a tribute of Karako to the Imperial household. The oldest documented record on 'fu' is the description of 'fu' in the article dated June 30, 1352, in "Kagenki" which was written during the period of the Northern and Southern Courts (Japan) (and it is said that 'utomu' which was mentioned along with 'fu' in that article is the oldest documented record on udon - Japanese wheat noodles). As the Zen sect gained popularity, fu began to be used in the Buddhist cuisine and kaiseki ryori (a simple meal served before a ceremonial tea), becoming a common food item on dining tables in Japan.