Fermented tofu (also called fermented bean curd, white bean-curd cheese, tofu cheese, soy cheese or preserved tofu) is a Chinese condiment consisting of a form of processed, preserved tofu used in East Asian cuisine. The ingredients typically are soybeans, salt, rice wine and sesame oil or vinegar. In mainland China the product is often freshly distributed. In overseas Chinese communities living in Southeast Asia, commercially packaged versions are often sold in jars containing blocks 2- to 4-cm square by 1 to 2 cm thick soaked in brine with select flavorings.
History
According to the 1596 Compendium of Materia Medica written by the Chinese polymath Li Shizhen during the Ming dynasty, the creation of soybean curd is attributed to the Han dynasty Prince Liu An (179 – 122 BC), prince of Huainan. Manufacturing began during the Han dynasty in China after it was created.
Names
In Mandarin, the product is generally known as dòufǔrǔ (), "dòurǔ" () or fǔrǔ () though in southwest China it is often known as lǔfǔ (). In English it is sometimes referred to as "soy cheese".
Nutrition
Nutritional value
Fermented bean curd contains organic acids, alcohol, esters and other flavor primitives. It contains a large amount of hydrolyzed protein, free amino acids, fat, carbohydrates, thiamine, riboflavin, oxalic acid, calcium, phosphorus and other nutritional ingredients. It contains no cholesterol. The amount of protein in fermented tofu is about 12–22%.
Ho et al. (1989) compared the volatile flavor compounds of red fermented bean curd and white fermented bean curd. Red fermented bean curd contains much larger amounts of alcohols, esters, and acids than the white variety. This may be due to the fermentation of red rice by Monascus spp. The differences in nutritional properties and fermentation between the two varieties are accompanied by differences in flavor and colour.
Health care function
The Food Encyclopedia, written by Wang Su-Hsiung (1861) of the Qing dynasty, made reference to preserved bean curd as superior to difficult-to-digest, hardened tofu especially for the elderly, children, and ill persons. Fermented bean curd is reportedly easier to digest than unfermented bean curd, because it is made through the fermentation process of mold, making the protein more digestible, absorbable, and richer in vitamins. And the microorganisms decompose the phytic acid in the beans, making minerals such as iron and zinc, which are initially poorly absorbed in soybeans, more easily absorbed by the body. So it may be easier for patients, elderly, or children to eat and absorb the nutrients.
It has been suggested that fermented bean curd may have certain health benefits, although there is insufficient data to confirm these claims. One report claims that the fermentation process generates isoflavones, and that fermented bean curd could reduce the risk of coronary heart disease, lower blood pressure, and prevent osteoporosis.
Characteristics
Fermented bean curd has a special mouthfeel similar to certain dairy products due to the breakdown of its proteins which takes place during the air drying and fermentation. Lacking strong flavor prior to fermentation, fermented bean curd takes on the aroma and flavor of its marinade. The flavor is salty with mild sweetness. The texture and taste of fermented bean curd resembles a firm, smooth paste not unlike creamy blue cheese. (Indeed, this kind of tofu is sometimes called "Chinese cheese" in English.) Refrigerated, it can be kept for several years, during which time its flavor is believed to improve.
Culinary use
Fermented tofu is commonly used as a condiment, combined into sauces to accompany hot pot, or consumed at breakfast to flavor rice, porridge, gruel, congee, or erkuai. Usually either several bricks are placed in a small bowl covered in the flavored brine or one to one half bricks are placed into a bowl. Then, chunks are broken off the brick and consumed with a mouthful of porridge or gruel. The brine may also be used for flavoring. Fermented bean curd can also be added in small amounts, together with its brine, to flavor stir-fried or braised vegetable dishes (particularly leafy green vegetables such as water spinach). In the Chaoshan region of China, fermented tofu is the main ingredient used to make a stuffed biscuit known as furu bing.