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Tofu

2007 Schools Wikipedia Selection. Related subjects: Food and agriculture

                                                  Tofu / Doufu / Bean curd
                                     Seasoned tofu cubes in a Chinese dish
                                                              Burmese name
        Image:Bscript_pebya.png (pebya/péprā:) or Image:Bscript_topu.png
                                                           (tofu/tiuphü:)
                                                            Cambodian name
                                                                     to hu
                                                              Chinese name
                                       Chinese characters 豆腐 or 荳腐
                                  Mandarin romanizations dòufǔ ( Pinyin)
                                                      tou-fu ( Wade-Giles)
                                      Min Nan romanization tāu-hū ( POJ)
                                                             Filipino name
                                                                     tokwa
                                                           Indonesian name
                                                                      tahu
                                                             Japanese name
                                                              Kanji 豆腐
                                                              Romaji tōfu
                                                               Korean name
                                                             Hangul 두부
                                                 Revised Romanization dubu
                                                    McCune-Reischauer tubu
                                                            Malaysian name
                                                                     tauhu
                                                                Tamil name
                                                                      tahu
                                                                 Thai name
                                 เต้าหู้ ( IPA: [tâohûː])
                                                           Vietnamese name
                                    Quốc Ngữ đậu phụ (đậu hũ)

   Tofu, also called doufu (often in Chinese recipes) or bean curd
   (literal translation), is a food of Chinese origin, made by coagulating
   soy milk, and then pressing the resulting curds into blocks. The making
   of tofu from soy milk is similar to the technique of making cheese from
   milk. Wheat gluten, or seitan, in its steamed and fried forms, is often
   mistakenly called "tofu" in Asian or vegetarian dishes.

Production

   Tofu is made by coagulating soy milk and pressing the resulting curds.
   Although pre-made soy milk may be used, most tofu producers begin with
   their own soy milk, which is produced by soaking, grinding, boiling,
   and straining dried (or, more rarely, fresh) soybeans.

   Coagulation of the protein and oil ( emulsion) suspended in the boiled
   soy milk is the most important step in the production of tofu. This
   process is accomplished with the aid of coagulants. Two types of
   coagulants (salts and acids) are used commercially . The third type of
   coagulant, enzymes, is not yet used commercially but shows potential
   for producing both firm and "silken" tofu:
    1. Salt coagulants
          + Calcium sulfate (gypsum) and calcium chloride : The
            traditional, and most widely used coagulant to produce Chinese
            style tofu. It produces a tofu that is tender but slightly
            brittle in texture. The coagulant itself has no perceivable
            taste. Use of this coagulant also makes a tofu that is rich in
            calcium, an important mineral for treating and preventing
            osteoporosis. As such, many tofu manufacturers choose to use
            this coagulant to be able to market their tofu as a good
            source of calcium.
          + Magnesium chloride: The coagulant used to make Japanese style
            tofu with smooth and tender texture. In Japan, a white powder
            called nigari, which consists primarily of magnesium chloride,
            is produced from seawater after the sodium chloride is removed
            and the water evaporated. Depending on its production method,
            nigari may also contain small quantities of magnesium sulfate
            (Epsom salt), potassium chloride, calcium chloride, and trace
            amounts of other naturally occurring salts. Although the term
            nigari is derived from nigai, the Japanese word for "bitter,"
            neither nigari nor pure magnesium chloride imparts a
            perceivable taste to the finished tofu.
    2. Acid coagulants
          + Glucono delta-lactone (GDL): A naturally occurring organic
            acid also used in cheese making, which produces a very fine
            textured tofu that is almost jelly-like. This coagulant is
            used especially for "silken" and softer tofus, and confers an
            almost inperceptable sour taste to the finished product.
            Commonly used together with Calcium sulphate to give soft
            tofus a smooth tender texture.
    3. Enzyme coagulants
          + Among enzymes that have been shown to produce tofu are papain,
            and alkaline and neutral proteinases from microorganisms. In
            the case of papain, the enzyme to substrate ratio, by weight,
            was held constant at 1:400. An aliquot of 1% crude papain was
            added to "uncooked" soy milk at room temperature and heated to
            90–100 celsius .

   Contemporary tofu manufacturers may choose to use one or more of these
   coagulants, since they each play a role in producing a desired texture
   in the finished tofu. Different textures result from different pore
   sizes and other microsopic features in tofus produced using each
   coagulant. The coagulant mixture is dissolved into water, and the
   solution is then stirred into boiled soy milk until the mixture curdles
   into a soft gel.

   The curds are processed differently depending on the form of tofu that
   is being manufactured. For soft silken tofu ( 嫩 豆 腐; nèn doùfu) or tofu
   flower ( 豆 花, dòuhuā) the soy milk is curdled directly in the tofu's
   selling package. For standard firm Asian tofu, the soy curd is cut and
   strained of excess liquid using cheese cloth or muslin and then lightly
   pressed to produce a soft cake. Firmer tofus, such as Asian dry tofu (
   荳 乾) or Western types of tofu, are further pressed to remove even more
   liquid. The tofu curds are allowed to cool and become firm. The
   finished tofu can then be cut into pieces, flavoured or further
   processed.

   Although tartness is sometimes desired in dessert tofu, the acid used
   in flavouring is usually not the primary coagulant since it is not
   desirable to the flavour or texture of the resulting tofu to add it in
   a sufficiently high concentration as to induce coagulation. A sour
   taste in tofu and a slight cloudiness in its storing liquid is also
   usually an indication of bacterial growth and, hence, spoilage.

Varieties

   There is a wide variety of tofu available in the both western and
   eastern markets. Despite the daunting variety, tofu products can be
   split into two main categories: fresh tofu, which is produced directly
   from soy milk, and processed tofu, which is produced from fresh tofu.
   Tofu production also creates important side products which are often
   used in various cuisines.

Fresh tofu

   Depending on the amount of water that is extracted from the tofu curds,
   fresh tofu can be divided into three main varieties.
   Silken tofu with soy sauce and a decorative carrot slice
   Enlarge
   Silken tofu with soy sauce and a decorative carrot slice
     * Soft/silken tofu (嫩豆腐 or 滑豆腐, nèn doùfu or huá doùfu, in Chinese,
       lit. "soft tofu" or "smooth tofu"; 絹漉し豆腐, kinugoshi tōfu in
       Japanese, lit. "silk-filtered tofu"; 순두부, sundubu in Korean, lit.
       "mild tofu"): This undrained tofu contains the highest moisture
       content of all fresh tofus Its texture can be described as similar
       to that of very fine custard. In Korea and Japan, traditional soft
       tofu is made with seawater. Tofu flower (豆花, doù huā or 豆腐花, doùfu
       huā in Chinese), or tofu brain (豆腐腦, doùfu naǒ in Chinese), often
       eaten as a dessert, but sometimes with salty pickles or hot sauce
       added instead, is another type of soft tofu with an even higher
       moisture content. Because it is nearly impossible to pick up this
       type of tofu with chopsticks, it is generally eaten with a spoon.
     * Asian firm tofu (simply called 豆腐 doùfu in Chinese; 木綿豆腐, momendōfu
       in Japanese, lit. "cotton tofu"): Although drained and pressed,
       this form of fresh tofu still contains a great amount of moisture.
       It has the firmness of raw meat but bounces back readily when
       pressed. The texture of the inside of the tofu is similar to that
       of a firm custard. The skin of this form of tofu has the pattern of
       the muslin used to drain it and is slightly more resilient to
       damage than its inside. Can be picked up easily with chopsticks.
     * Western firm/dried tofu (豆乾, doù gān in Chinese, lit. "dry tofu"):
       An extra firm variety of tofu with the least amount of moisture of
       all fresh tofus. It has the firmness of fully cooked meat and a
       somewhat rubbery feel similar to paneer. When sliced thinly, this
       tofu can be crumbled easily. The skin of this form of tofu has the
       pattern of the muslin used to drain and press it. Western firm tofu
       is milled and reformed after the pressing and sometimes lacks the
       skin with its cloth patterning. One variety of dried tofu pressed
       especially flat and is sliced into long strings with a cross
       section smaller than 2 mm × 2 mm. Shredded dried tofu (荳乾絲, doù gān
       sī in Chinese), which looks like loose cooked noodles, and can be
       served cold, stir-fried, or similar in style to Japanese aburage.

   Fresh tofu is usually sold completely immersed in water to maintain its
   moisture content.

Processed tofu

   Many forms of processed tofus exist, due to the varied ways in which
   fresh tofu can be used. Some of these techniques likely originate from
   the need to preserve tofu before the days of refrigeration, or to
   increase its shelf life and longevity. Other production techniques are
   employed to create tofus with unique textures and flavours .

Fermented

     * Pickled tofu ( 豆 腐 乳 in Chinese, pinyin: dòufu rǔ, lit. "tofu
       dairy," or 腐 乳; chao in Vietnamese): Also called "preserved tofu"
       or "fermented tofu," this food consists of cubes of dried tofu that
       have been allowed to fully air-dry under hay and slowly ferment
       from aerial bacteria . The dry fermented tofu is then soaked in
       salt water, Chinese wine, vinegar, and minced chiles, or a unique
       mixture of whole rice, bean paste, and soybeans. In the case of red
       pickled tofu ( 紅 豆 腐 乳 in Chinese, Pinyin: hóng dòufu rǔ), red
       yeast rice (cultivated with Monascus purpureus) is added for
       colour.
     * Stinky tofu ( 臭 豆 腐 in Chinese, Pinyin: chòu dòufu): A soft tofu
       that has been fermented in a unique vegetable and fish brine . The
       blocks of tofu smell strongly of certain pungent cheeses, and are
       described by many as rotten and fecal. Despite its strong odour,
       the flavour and mouthfeel of stinky tofu is appreciated by
       aficionados, who describe it as delightful. The texture of this
       tofu is similar to the soft Asian tofu that it is made from. The
       rind that stinky tofu develops from frying is said to be especially
       crisp, and is usually served with soy sauce, sweet sauce, and/or
       hot sauce.

Flavoured

   Almond "tofu," which is not made of soy milk but rather from gelatin or
   agarose
   Enlarge
   Almond "tofu," which is not made of soy milk but rather from gelatin or
   agarose

   Flavourants can be mixed directly into curdling soy milk while the tofu
   is being produced.
     * Sweet: Common sweet dessert tofus include peanut tofu (落花生豆腐,
       luòhuā shēng doùfu in Chinese and jimami-dōfu in Japanese), almond
       tofu (杏仁豆腐, xìng rén doùfu in Chinese; 杏仁豆腐, annindōfu in
       Japanese), mango tofu, and coconut tofu. In order to produce these
       forms of tofu, sugar, fruit acids, and flavourants are mixed into
       soy milk prior to curdling. Most sweet tofus have the texture of
       silken tofu and are served cold.
          + Products called "almond tofu" in some cases are actually not
            made from tofu but are instead gelatinous desserts made from
            agar or gelatin and whitened with milk or coconut milk. In
            Japan these are canned with syrup and sold as a sweet dessert.
     * Savory: Egg tofu (蛋豆腐; dàn doùfu, in Chinese) (玉子豆腐; yù zǐ doùfu;
       lit. "jade tofu," in Chinese; 玉子豆腐; tamagodōfu, in Japanese) is the
       main type of savory flavoured tofu. Whole beaten eggs are filtered
       and incorporated into the soy milk before the coagulant is added.
       The mixture is filled into tube shaped plastic bags and allowed to
       curdle. The tofu is then cooked in its packaging and sold. Egg tofu
       has a pale golden colour that can be attibuted to the addition of
       egg and, occasionally, food colouring. This tofu has a fuller
       texture and flavour than silken tofu, which can be attributed to
       the presence of egg fat and protein.

Fried

     * With the exception of the softest tofus, all forms of tofu can be
       fried. Thin and soft varieties of tofu are deep fried in oil until
       they are light and airy in their core ( 豆 泡 in Chinese, dòupào,
       lit. "bean bubble," describing the shape of the fried tofu as a
       bubble).
     * Tofus such as firm Asian and dry tofu, with their lower moisture
       content, are cut into bite-sized cubes or triangles and deep fried
       until they develop a golden-brown, crispy surface (炸豆腐 in Chinese,
       jadòufu, lit. "fried tofu"). These may be eaten by themselves or
       with a light sauce, or further cooked in liquids; they are also
       added to hot pot dishes or included as part of the vegetarian dish
       called luohan zhai.

Frozen

   Thawed and sliced frozen tofu
   Enlarge
   Thawed and sliced frozen tofu
     * Thousand layer tofu ( 千 葉 豆 腐 or 冰 豆 腐 in Chinese, lit. "thousand
       layer tofu" or "frozen tofu"): By freezing tofu, the large ice
       crystals that develop within the tofu results in the formation of
       large cavities that appear to be layered (pseudostratified). The
       frozen tofu takes on a yellowish hue in the freezing process.
       Thousand layer tofu is commonly made at home from Asian soft tofu
       though it is also commercially sold as a regional specialty in
       parts of Taiwan. This tofu is defrosted and squeezed of moisture
       prior to use.
     * Japanese freeze-dried tofu (kōyadōfu, 高 野 豆 腐 in Japanese): The
       name comes from Mount Koya, a centre of Japanese Buddhism famed for
       its shōjin ryōri, or traditional Buddhist vegetarian cuisine. It is
       excellent for camping, in that it is very light, may be sold
       flattened, and makes a very filling nutritious meal on the road.
       Like many freeze-dried foods, it is soaked in hot water or broth
       before eating, taking on a spongy texture when reconstituted.
       Freeze-dried tofu is also found in instant soups (such as miso
       soup), in which the toppings are freeze-dried and stored in sealed
       pouches.

Byproducts of tofu production

   Tofu production creates some edible byproducts. Food products are made
   from the protein-oil film, or "skin," which forms over the surface of
   boiling soy milk in an open shallow pan. The leftover solids from
   pressing soy milk is called okara.

Yuba

   Boiling of soy milk, in an open shallow pan , produces a film or skin
   composed primarily of a soy protein-lipid complex on the liquid surface
   . The films are collected and dried into yellowish sheets known as yuba
   or soy milk skin (腐皮, fǔ pí in Chinese; 湯葉, yuba in Japanese). Its
   approximate composition is : 50–55% protein, 24–26% lipids (fat), 12%
   carbohydrate, 3% ash, and 9% moisture.

   The yuba can also be bunched up to stick form and dried into something
   known as "tofu bamboo" (腐竹, fǔ zhú in Chinese; kusatake, Japanese), or
   a myriad of other forms. Since tofu skin has a soft yet rubbery
   texture, it is folded or shaped into different forms and cooked further
   to imitate meat in vegetarian cuisine.

   Some factories dedicate production to tofu skin and other soy membrane
   products.

Okara

   Okara (雪花菜, xuě huā caì, lit. "snowflake vegetable"; 豆腐渣, doùfu zhā,
   lit. "tofu sediment/residue"; kongbiji in Korean), sometimes known in
   the west as soy pulp, is the fibre, protein, and starch left over when
   soy milk has been extracted from ground soaked soybeans . Although it
   is mainly used as animal feed in most tofu producing cultures, it is
   sometimes used in Japanese and Korean cuisines. It is also an
   ingredient for vegetarian burgers produced in many western nations.
   Okara is rarely seen or used in Chinese cuisine.

Tofu made from other legumes

     * Black bean tofu (黑豆花): A type of tofu made from black beans and
       soybeans, which is usually made into tofu flower ( 豆 花, dòuhuā)
       rather than firm or dry tofu. The texture of black bean tofu is
       slighty more gelatinous than regular tofu flower and the colour is
       greyish in tone. This type of tofu is eaten for the earthy "black
       bean taste."
     * Burmese tofu (to hpu in Burmese): A type of tofu made from chick
       pea (chana dal) flour instead of soybeans; the Shan variety uses
       yellow split peas instead. Both types are yellow in colour and
       generally found only in Myanmar, though the Burman variety is also
       available in some overseas restaurants serving Burmese cuisine.
       Burmese Tofu Recipe

Preparation

   Tofu has very little flavour or smell on its own. As such, tofu can be
   prepared either in savoury or sweet dishes, acting as a canvas for
   presenting the flavours of the other ingredients used.

Western methods

   Generally, the firmer styles of tofu are used for kebabs, mock meats,
   and dishes requiring a consistency that holds together, while the
   softer styles can be used for desserts, soups, shakes, and sauces.

   Firm western tofus can be barbecued since they will hold together on a
   barbecue grill. These types of tofu are usually marinated overnight as
   the marinade does not easily penetrate the entire block of tofu. Grated
   firm western tofu is sometimes used in conjunction with TVP as a meat
   substitute. Softer tofus are sometimes used as a dairy free or low
   calorie filler. Silken tofu may be used to replace cheese in certain
   dishes (such as lasagna).

   The versatility of tofu and soy protein can be industrially processed
   to match the textures and flavoured to the likes of cheese, pudding,
   eggs, bacon, etc. Tofu's texture can also be altered by freezing,
   pureeing, and cooking. In the Americas, Europe, Australia and New
   Zealand, tofu is frequently associated with vegetarianism and veganism
   as it is a source of high quality non-animal protein.

Eastern methods

   In Asian cooking, tofu is eaten in a myriad of ways, including raw,
   stewed, stir-fried, in soup, cooked in sauce, or stuffed with fillings.

Lightly flavoured

   The light greenish "bean" smell of tofu is much enjoyed in East Asian
   cuisines and fresh tofu is often eaten plain or simply flavoured.

   In Japan, a common lunch in the summer months is hiyayakko ( 冷 奴),
   silken or firm Asian tofu served with freshly grated ginger, scallions,
   and soy sauce. In many parts of China, fresh tofu is similarly eaten
   with soy sauce or further flavoured with katsuobushi shavings, century
   eggs ( 皮 蛋), and sesame seed oil.
   Dòuhuā (豆花), is a soft tofu dish. The fresh tofu is served warm and
   here dressed with sweet syrup. Lamma Island, Hong Kong.
   Enlarge
   Dòuhuā (豆花), is a soft tofu dish. The fresh tofu is served warm and
   here dressed with sweet syrup. Lamma Island, Hong Kong.

   Dòuhuā ( 豆 花) is served with toppings like boiled peanuts, azuki beans,
   cooked oatmeal, tapioca, mung beans and a syrup flavored with ginger or
   almond. During the summer, dòuhuā is served with crushed ice; in the
   winter, it is served warm.

   In Korean cuisine, dubu jorim consists of cubes of firm tofu that are
   pan fried and seasoned with soy sauce, garlic, and other ingredients.
   Cubes of cold, uncooked tofu seasoned with soy sauce, scallions, and
   ginger, prepared in a manner similar to the Japanese hiyayakkoare also
   enjoyed.

Fried

   A common cooking technique in many parts of East and Southeast Asia
   involves deep frying tofu in vegetable oil, sunflower oil and canola
   oil to varied results. Although, tofu is often sold preprocessed into
   fried items, pre-fried tofu is seldom eaten directly and requires
   additional cooking. Depending on the type of tofu used, the texture of
   deep fried tofu may range from crispy on the outside and custardy on
   the inside, to puffed up like a plain doughnut. The former is usually
   eaten plain in Chinese cuisine with garlic soy sauce, while the latter
   is either stuffed with fish paste or cooked in soups. In Japan, cubes
   of lightly coated and fried tofu topped with a kombu dashi-based sauce
   are called agedashi-dofu (揚げ出し豆腐). Soft tofu that has been thinly
   sliced and deep fried, known as aburage in Japan, is commonly blanched,
   seasoned with soy sauce and mirin and served in dishes such as kitsune
   udon. Aburage is sometimes also cut open to form a pocket and stuffed
   with sushi rice; this dish is called inarizushi (稲荷寿司) .

Soups, stews, and braised dishes

   A rather famous hot Sichuan preparation using firm Asian tofu is mápó
   dòufu ( 麻 婆 豆 腐). This involves braised tofu in a pork, chili, and a
   fermented bean paste sauce. In the Shanghai region it is called málà
   dòufu ( 麻 辣 豆 腐).

   Dried tofu is usually not eaten raw but first stewed in a mixture of
   soy sauce and spices. Some types of dried tofu are preseasoned with
   special blends of spices, so that the tofu may either be called "five
   spice tofu" (五香豆腐) or "soy sauce stewed tofu" (鹵水豆腐). Dried tofu is
   typically served thinly sliced with chopped green onions or with slices
   of meat for added flavor. Most dried tofu is sold after it has been
   fried or pre-stewed by tofu vendors.

   Soft tofu can also be broken up or mashed and mixed with raw
   ingredients prior to being cooked. For example, Japanese ganmodoki is a
   mixture of chopped vegetables and mashed tofu. The mixture is bound
   together with starch and deep fried. Chinese families sometimes make a
   steamed meatloaf or meatball dish from equal parts of coarsely mashed
   tofu and ground pork. In India, tofu is also used as a low fat
   replacement for paneer providing the same texture with similar taste.

   Tofu bamboos are often used in lamb stew or in a dessert soup. Tofu
   skins are often used as wrappers in dim sum. Freeze-dried tofu and
   frozen tofu is rehydrated enjoyed in savoury soups. These products are
   often taken along on camping trips since a small bag of these dried
   tofu can provide protein for many days.

   In Korean cuisine, soft tofu (sundubu in Korean) is used to make a
   thick soup called sundubu jjigae (순두부 찌개).

As flavouring

   Pickled tofu is commonly used in small amounts together with its
   soaking liquid to flavour stir-fried or braised vegetable dishes
   (particularly leafy green vegetables like water spinach). It is often
   eaten directly as a condiment with rice or congee.

History

   Very little is known about the exact historic origins of tofu and its
   method of production. While there are many theories regarding tofu's
   origins, historical information is scarce enough as to relegate the
   status of most theories to either speculation or legend. Like the
   origins of cheese and butter, the exact origin of tofu production may
   never be known or proven.

   What is known is that tofu production is an ancient technique. Tofu was
   widely consumed in ancient China, and techniques for its production and
   preparation were eventually spread to many other parts of Asia.

Three theories of origin

   The most commonly held of the three theories of tofu's origin maintains
   that tofu was invented in Northern China around 164 BC by Lord Liu An,
   a prince during the Han Dynasty. Although this is possible, the paucity
   of concrete information about this period makes it difficult to
   conclusively determine whether or not Liu An invented the method for
   making tofu. Furthermore, in Chinese history, important inventions were
   often attributed to important leaders and figures of the time.

   Another theory states that the production method for tofu was
   discovered accidentally when a slurry of boiled, ground soybeans was
   mixed with impure sea salt. Such sea salt would likely have contained
   calcium and magnesium salts, allowing the soy mixture to curdle and
   produce a tofu-like gel.^1 This may have possibly been the way that
   tofu was discovered, since soy milk has been eaten as a savory soup in
   ancient as well as modern times. Despite its technical plausibility,
   there is little evidence to prove or disprove that tofu production
   originated in this way.

   The last group of theories maintains that the ancient Chinese learned
   the method for the curdling of soy milk by emulating the milk curdling
   techniques of the Mongolians or East Indians. For, despite their
   advancement, no technology or knowledge of culturing and processing
   milk products existed within ancient Chinese society. The primary
   evidence for this theory lies with the etymological similarity between
   the Chinese term for Mongolian fermented milk (rufu, which literally
   means "milk spoiled") and the term doufu or tofu. Although intriguing
   and possible, there is no evidence to substantiate this theory beyond
   the point of academic speculation.

Established history of tofu

   Although its development likely preceded Liu An, tofu is known to have
   been a commonly produced and consumed food item in China by the 2nd
   century BC. Although the varieties of tofu produced in ancient times
   may not have been identical to those of today, descriptions from
   writings and poetry of the Song and Yuan Dynasty show that the
   production technique for tofu had already been standardized by then, to
   the extent that they would be similar to tofu of contemporary times.

   Tofu and its production technique were subsequently introduced into
   Japan in the Nara period (late eighth century) as well as other parts
   of East Asia. This spread likely coincided with the spread of Buddhism
   as it is an important source of proteins in the religion's vegetarian
   diet. Since then, tofu has become a staple in many countries, including
   Vietnam, Thailand, and Korea, with subtle regional variations in
   production methods, texture, flavour, and usage.

   Tofu was not well known to most Westerners before the middle of the
   20th century. However, with increased cultural contact and an interest
   in vegetarianism, tofu has become a more familiar product to
   Westerners.

Nutrition and health information

   Tofu is low in calories, contains beneficial amounts of iron
   (especially important for women of child bearing age) and has no
   cholesterol (a risk factor for heart disease). Depending on the
   coagulant used in manufacturing, the tofu may also be high in calcium
   (important for bone development and maintenance) and magnesium
   (especially important for athletes).

Protein

   Tofu is relatively high in protein, about 10.7% for firm tofu and 5.3%
   for soft "silken" tofu with about 2% and 1% fat respectively as a
   percentage of weight.^3

   In 1995, the New England Journal of Medicine (Vol. 333, No. 5)
   published a report from the University of Kentucky entitled,
   "Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids."
   It was financed by the PTI division of DuPont,"The Solae Co." St.
   Louis, Missouri. This meta-analysis concluded that soy protein is
   correlated with significant decreases in serum cholesterol, Low Density
   Lipoprotein LDL (bad cholesterol) and triglyceride concentrations.
   However, High Density Lipoprotein HDL (good cholesterol) did not
   increase. Soy phytoestrogens ( isoflavones: genistein and daidzein)
   adsorbed onto the soy protein were suggested as the agent reducing
   serum cholesterol levels. On the basis of this research PTI, in 1998,
   filed a petition with Food and Drug Administration for a health claim
   that soy protein may reduce cholesterol and the risk of heart disease.

   The FDA granted this health claim for soy: "25 grams of soy protein a
   day, as part of a diet low in saturated fat and cholesterol, may reduce
   the risk of heart disease." One serving, (1 cup or 240 mL) of soy milk,
   for instance, contains 6 or 7 grams of soy protein.

   In January 2006 an American Heart Association review (in the journal
   Circulation) of a decade long study of soy protein benefits cast doubt
   on the FDA allowed "Heart Healthy" claim for soy protein. Among the
   conclusions the authors state, "In contrast, soy products such as tofu,
   soy butter, soy nuts, or some soy burgers should be beneficial to
   cardiovascular and overall health because of their high content of
   polyunsaturated fats, fibre, vitamins, and minerals and low content of
   saturated fat. Using these and other soy foods to replace foods high in
   animal protein that contain saturated fat and cholesterol may confer
   benefits to cardiovascular health."

Isoflavones

   Soy isoflavones have not been shown to reduce post menopause "hot
   flashes" in women and the efficacy and safety of isoflavones to help
   prevent cancers of the breast, uterus or prostate is in question. Thus,
   soy isoflavone supplements in food or pills is not recommended. The
   original paper is in the journal Circulation: January 17, 2006.

   A study done by the Pacific Health Research Institute followed over
   3000 Japanese men between 1965 and 1999, which showed a positive
   correlation between brain atrophy and consumption of tofu. .
   Nevertheless, this is a single study and by itself, does not show
   conclusively that soy isoflavones causes brain atrophy.

   This study by L.R. White, et al., from the National Institute of Aging,
   NIH, was rejected as not credible by the Food and Drug Administration
   when it issued its health claim for soy: "25 grams of soy protein a
   day, as part of a diet low in saturated fat and cholesterol, may reduce
   the risk of heart disease."

Sales and distribution

   In the West, tofu can be obtained in Asian markets, farmers' markets,
   and health food stores. Depending on its local popularity, many grocery
   stores also stock tofu. The largest provider of tofu products in the
   United States is Hong Kong-based Vitasoy, which also manufactures the
   brands Nasoya and Azumaya. Another major brand is Mori-Nu (Morinaga
   Nutritional Foods), a subsidiary of Morinaga Milk Company of Japan,
   which pioneered the sale of shelf-stable, aseptically packaged tofu.

   In the East, tofu may be produced locally by relatively small vendors
   or distributed widely by large national brands. Fresh tofu is usually
   bought from local vendors and is sold directly from large bins or pots
   at street markets. Asian firm tofu and "tofu flower" are commonly sold
   in this manner and are usually no more than a few hours old. Tofu that
   is sold by large manufacturers often comes packaged in sealed plastic
   cartons or tubes, and may be at most two weeks old. Most silken and
   flavoured tofus are produced by large factories. This is due to the
   fact that such factories have the facilities to meet the required
   sanitary conditions for production of these forms of tofu on a large
   scale. In Chinese supermarkets, tofu can be found in many different
   flavours and grades of consistency.

Etymology

   The English word "tofu" comes from the Japanese tōfu (豆腐),^5 which
   itself derives from the Chinese dòufu (豆腐 or 荳腐). Although in both
   languages the characters together translate as "bean curd," the literal
   meaning of the individual characters is "bean" ( 豆) and "curdled" ( 腐).

Choosing Tofu

   Unless one purchases it in sterilized containers, tofu does require
   some choosing when purchasing and some care while storing:
     * Tofu can easily be spoiled if not refrigerated properly during
       transportation; any trace of sour odour or taste is a tell-tale
       sign of staleness or spoilage.
     * Smaller supermarkets may sell sour tofu because some do not use
       refrigerated trucks for delivery.
     * Once purchased, unpackaged tofu should be kept in the refrigerator.
       The water in which the tofu is kept should be changed on a daily
       basis and the tofu should be consumed or cooked within several
       days. Tofu in sealed packages can be kept from one to several weeks
       in the refrigerator. Tofu packaged in aseptic Tetra Brik containers
       has a shelf life of one year if unopened.

Myths

   The Chinese have a myth that if one eats tofu, one should not eat or
   drink honey for fear that this might cause death.
   Retrieved from " http://en.wikipedia.org/wiki/Tofu"
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   with only minor checks and changes (see www.wikipedia.org for details
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