Difference between revisions of "Tofu" - New World Encyclopedia

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'''Tofu''', also '''tōfu''' (the Japanese [[Romanization of Japanese|Romaji]] spelling),  '''doufu''' (the Chinese [[Pinyin]] spelling often used in [[Chinese cuisine|Chinese]] recipes) or '''bean curd''' (the literal translation), is a [[food]] of [[China|Chinese]] origin,<ref name=Soya>{{cite web|url=http://www.soya.be/history-of-tofu.php|title=History of Tofu|accessdate=2008-01-05|publisher=Soya}}</ref> made by [[coagulation (milk)|coagulating]] [[soy milk]], and then pressing the resulting curds into blocks. There are many different varieties of tofu, including fresh tofu and tofu that has been processed in some way. Tofu has very little flavor or smell on its own, so it can be used either in savory or sweet dishes, and is often seasoned or marinated to suit the dish.
 
  
The production of tofu from soy milk is similar to the production of [[cheese]] from [[milk]], although some tofu is made by processing non-soy products, such as almonds or black beans. The byproduct of the process is [[Okara (food)|soy pulp]] (also called ''okara'' in [[Japanese (language)|Japanese]]).
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'''Tofu''', also '''tōfu''' (the Japanese Romaji spelling), '''doufu''' (the Chinese Pinyin spelling often used in [[Chinese cuisine|Chinese]] recipes) or '''bean curd''' (the literal translation), is a [[food]] of [[China|Chinese]] origin, made by coagulating [[soy milk]], and then pressing the resulting curds into blocks. There are many different varieties of tofu, including fresh tofu, tofu processed or preserved in a variety of ways, and tofu by-products such as tofu skins and soy pulp ([[Japanese language|Japanese: ''okara'']]). Tofu has very little flavor or smell on its own, so it can be used either in savory or sweet dishes, and is often seasoned or marinated to suit the dish. Some tofu is made by processing non-[[soybean|soy]] products, such as [[almond]]s or black beans.  
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Tofu originated in ancient [[China]], but little else is known about the origins of tofu and its method of production. Tofu and its production technique were introduced into [[Japan]] in the [[Nara period]] (late eighth century), and spread to other parts of [[East Asia]], where it has become a core ingredient of many cuisines. Tofu is low in [[calorie]]s, contains beneficial amounts of [[iron]] (especially important for women of child-bearing age) and has no [[saturated fat]] or [[cholesterol]]. 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). Tofu also contains soy [[isoflavones]], which can mimic natural human [[estrogen]]s and may have a variety of harmful or beneficial effects when eaten in sufficient quantities.
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==Etymology==
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The English word "tofu" comes from the [[Japanese language|Japanese]] ''tōfu'' ({{lang|ja|豆腐}}), which derives from the [[Chinese language|Chinese]] ''dòufǔ'' ({{lang|zh|豆腐}} or {{lang|zh|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).<ref>''American Heritage Dictionary of the English language'' (Boston: Houghton Mifflin, 2006, ISBN 0395825172).</ref>
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==History==
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Tofu originated in ancient [[China]].<ref name=Soya>[http://www.soya.be/history-of-tofu.php History of Tofu]. ''Soya''. Retrieved December 16, 2015. </ref> There are many theories regarding the origins of tofu, but little historical information to prove or disprove them. It is known that tofu was widely consumed in ancient China, and that techniques for its production and preparation eventually spread to many other parts of [[Asia]].
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===Three theories of origin===
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The most common theory about the origin of tofu origin maintains that it was invented in northern China around 164 B.C.E. by Lord [[Liu An]], a [[Han Dynasty]] prince. Chinese [[folklore]] often attributes important inventions to well-known historical figures;<ref name=bookoftofu>William Shurtleff and Akiko Aoyagi, ''The Book of Tofu. Volume 1, Food for Mankind'' (Brookline, MA: Autumn Press, 1975, ISBN 0914398059). [http://www.soyinfocenter.com/HSS/tofu1.php  History of Tofu] Retrieved June 27, 2008.</ref><ref name=Morii>Genichi Morii and Haruo Isshi, ''Tofumichi'' (Tokyo: Shinchosha, 2004, ISBN 978-4104719013) (In Japanese)</ref> techniques of tofu production probably existed long before this time.
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Another theory is that the method for producing tofu was discovered accidentally when a slurry of boiled, ground [[soybean]]s was mixed with impure sea salt, containing calcium and magnesium salts, which caused the soy mixture to curdle and produce a tofu-like gel.<ref>Korean ''sundubu'' (soft tofu) is still produced in a similar manner, using seawater as a coagulant.</ref> Soy milk has been eaten as a savory soup since ancient times.<ref name=bookoftofu/>
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A third theory maintains that the ancient Chinese learned the method for the curdling of soy milk by emulating the milk curdling techniques of the [[Mongol|Mongolian]]s or East Indians. 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 in the etymological similarity between the Chinese term for Mongolian fermented milk (''rufu,'' which literally means "milk spoiled") and the term ''doufu'' or tofu.<ref name=bookoftofu/>
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===In Asia===
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Tofu is known to have been a commonly consumed food in [[China]] by the second century B.C.E. 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 Dynasty|Song]] and [[Yuan Dynasty|Yuan]] Dynasties show that the technique for the production of tofu had already been standardized by that time.
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In China, tofu is traditionally presented as a food offering when visiting the [[grave]]s of deceased relatives. According to tradition, tofu is the only food soft enough for the spirits (or ghosts), who have long ago lost their chins and jaws, to eat. Before [[refrigeration]] was available in China, tofu was often sold only during the winter time. During the warmer months, leftover tofu would be spoiled if not consumed within a day.  
  
Tofu originated in ancient [[China]],<ref name=Soya/> but little else is known about the origins of tofu and its method of production. 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 [[Buddhist cuisine|the religion's vegetarian diet]].<ref name=TofuDao />
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Tofu and its production technique were introduced into [[Japan]] in the [[Nara period]] (late eighth century) as well as to other parts of [[East Asia]]. The earliest documented record of tofu in Japan shows that the dish was served as an offering at the Kasuga Shrine in [[Nara]] in 1183.<ref>Donald Richie, ''A Taste of Japan'' (Kodansha, 2001, ISBN 4770017073).</ref> The rise in acceptance of tofu may have coincided with the rise of [[Buddhism]], as tofu is an important source of protein in a vegetarian diet.<ref name=Morii/> The book ''Tofu Hyakuchin'' ({{lang|ja|豆腐百珍}}), published during the [[Edo period]], lists 100 recipes for cooking tofu.
  
Tofu is low in [[calorie]]s, contains beneficial amounts of [[iron]] (especially important for women of child-bearing age) and has no [[saturated fat]] or [[cholesterol]].  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).  Tofu also contains soy [[isoflavones]], which can mimic natural human [[estrogen]]s and may have a variety of harmful or beneficial effects when eaten in sufficient quantities.
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Tofu has become a [[Staple food|staple]] in many countries, including [[Vietnam]], [[Thailand]], and [[Korea]], with subtle regional variations in methods of production, texture, flavor, and usage.
  
 
==Production==
 
==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 by making their own soy milk, which is produced by soaking, grinding, boiling, and straining dried (or, less commonly, fresh) [[soybeans]].
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The production of tofu from soy milk is similar to the production of [[cheese]] from [[milk]]. Tofu is made by coagulating soy milk and pressing the resulting curds. Although commercial soy milk may be used, most tofu producers begin by making their own soy milk, produced by soaking, grinding, boiling, and straining dried (or, less commonly, fresh) [[soybean|soybeans]]. Some non-soy products, such as almonds or black beans, are also processed to make tofu.
  
[[Coagulation (disambiguation)|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.<ref name=Zeki>{{Harvnb|Berk|1992}}, [http://www.fao.org/docrep/t0532e/t0532e10.htm#9.5 section 9.5]</ref> The third type of coagulant, enzymes, is not yet used commercially but shows potential for producing both firm and "silken" tofu.
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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 for commercial production.<ref name=Berk>Zeki Berk, [http://www.fao.org/docrep/t0532e/t0532e10.htm#9.5 "Technology of production of edible flours and protein products from soybeans."] Retrieved December 16, 2015. FAO agricultural services bulletin, (Rome: Food and Agriculture Organization of the United Nations, 1992. ISBN 978-9251031186). </ref> A third type of coagulant, enzymes, is not yet used commercially but shows potential for producing both firm and "silken" tofu.
  
 
===Salt coagulants===
 
===Salt coagulants===
*'''[[Calcium sulfate]]''' ([[gypsum]]): 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.
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*'''Calcium sulfate''' ([[gypsum]]): The traditional and most widely used coagulant to produce Chinese-style tofu is [[calcium sulfate]], which produces a tofu that is tender but slightly brittle in texture. The coagulant itself has no perceptible taste. Use of this coagulant also makes a tofu that is rich in calcium, an important [[mineral]] for treating and preventing [[osteoporosis]]. Many tofu manufacturers use calcium sulfate so that they can market their tofu as a good source of calcium.  
  
*Chloride-type Nigari salts or Lushui (卤水 in Chinese) - [[Magnesium chloride]] and [[calcium chloride]]: Both of these salts have a high solubility rate in water and affect soy protein in the same way, whereas [[gypsum]] is only very slightly soluble in water and acts differently in soy protein precipitation, the basis for tofu formation. These are the coagulants used to make tofu with a smooth and tender texture. In Japan, a white powder called ''[[nigari]]'', which consists primarily of magnesium chloride, is produced from [[Sea water|seawater]] after the [[sodium chloride]] is removed and the water evaporated, which is called Lushui (卤水) in China. Depending on its production method, ''nigari/Lushui'' 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. Calcium chloride is a common coagulant for tofu in North America.<ref name=Lui>{{Harvnb|Liu|1997}}.</ref>
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*Chloride-type Nigari salts or Lushui (卤水 in Chinese) - [[Magnesium chloride]] and [[calcium chloride]]: Both of these salts have a high solubility rate in water and affect soy protein in the same way; [[gypsum]] is only very slightly soluble in water and acts differently in soy protein precipitation. These coagulants produce tofu with a smooth and tender texture. In Japan, a white powder called ''nigari'' (lushui, 卤水, in China), which consists primarily of magnesium chloride, is produced from [[Sea water|seawater]] after the [[sodium chloride]] is removed and the water evaporated. Depending on how it is produced, ''nigari/lushui'' 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. Calcium chloride is commonly used as a coagulant for tofu in North America.<ref name=Liu>KeShun Liu, ''Soybeans: Chemistry, Technology, and Utilization'' (Springer, 1997, ISBN 978-0834212992). </ref>  
  
 
===Acid coagulants===
 
===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 imperceptible sour taste to the finished product.<ref name=GuoOno>{{Harvnb|Guo|Ono|2005}}.</ref> Commonly used together with calcium sulfate to give soft tofu a smooth tender texture.
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*'''Glucono delta-lactone''' (GDL): A naturally occurring organic acid also used in [[cheese]] making, GDL produces a very fine-textured tofu that is almost jelly-like. This coagulant is used especially for "silken" and softer tofus, and gives the finished product an almost imperceptible sour taste.<ref name=Guo>Shun-Tang Guo and Tomotada Ono, [http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2621.2005.tb07170.x “The Role of Composition and Content of Protein Particles in Soymilk on Tofu Curding by Glucono-δ-lactone or Calcium Sulfate,”] ''Journal of Food Science'' 70 (4) (2005): 258–262. Retrieved June 27, 2008. </ref> GDL is commonly used together with calcium sulfate, to give soft tofu a smooth tender texture.
  
 
===Enzyme coagulants===
 
===Enzyme coagulants===
*Among [[enzymes]] that have been shown to produce tofu are [[papain]], and alkaline and neutral [[Protease|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 degrees Celsius.<ref name=Lui/>
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*Among [[enzymes]] that have been shown to produce tofu are [[papain]], and [[alkaline]] and neutral proteases from [[microorganism]]s. In the case of papain, the enzyme to substrate ratio, by weight, was held constant at 1:400. An aliquot of 1 percent crude papain was added to "uncooked" soy milk at room temperature and heated to 90–100 degrees Celsius.<ref name=Liu/>
  
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.<ref name=GuoOno/> Different textures result from different pore sizes and other microscopic 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]].<ref name=Zeki/>
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Contemporary tofu manufacturers may use a combination of these coagulants to produce a desired texture in the finished tofu.<ref name=Guo/> Different textures result from a difference in pore sizes and other microscopic features in the tofus produced using each coagulant. The coagulant mixture is dissolved in water, and the solution is then stirred into boiled soy milk until the mixture curdles into a soft [[gel]].<ref name=Berk/>
  
The curds are processed differently depending on the form of tofu that is being manufactured. For soft silken tofu ({{lang|zh|[[wiktionary:嫩|嫩]][[wiktionary:豆|豆]][[wiktionary:腐|腐]]}}; ''nèn dòufǔ'') or tofu flower ({{lang|zh|[[wiktionary:豆|豆]][[wiktionary:花|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 ({{lang|zh|[[wiktionary:荳|荳]][[wiktionary:乾|乾]]}}) or Western types of tofu, are further pressed to remove even more liquid. In Vietnam, the curd is strained and molded in a square mold and the end product is called  
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The curds are processed differently, depending on the form of tofu that is being manufactured. For soft silken tofu ({{lang|zh|嫩豆腐}}; ''nèn dòufǔ'') or tofu flower ({{lang|zh|豆花}}, ''dòuhuā''), the soy milk is curdled directly in the container in which the tofu will be sold. For standard firm Asian tofu, the soy curd is cut and excess liquid is strained off using [[cheese cloth]] or [[muslin]], then the curds are lightly pressed into a soft cake. Firmer tofus, such as Asian dry tofu ({{lang|zh|荳乾}}) or Western types of tofu, are pressed to remove even more liquid. In Vietnam, the curd is strained and molded in a square mold, and the end product is called ''đậu khuôn'' (molded bean) or ''đậu phụ'' (one of the Vietnamese ways to pronounce the Chinese “doufu”). The tofu curds are allowed to cool and become firm. The finished tofu can then be cut into pieces, flavored or further processed.
''đậu khuôn'' (molded bean) or ''đậu phụ'' (one of the Vietnamese ways to pronounce the Chinese doufu). The tofu curds are allowed to cool and become firm. The finished tofu can then be cut into pieces, flavored or further processed.
 
  
Although tartness is sometimes desired in dessert tofu, the acid used in flavoring is usually not the primary coagulant since it is not desirable to the flavor or texture of the resulting tofu to add it in a sufficiently high concentration so 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.
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Although tartness is sometimes desired in dessert tofu, the [[acid]] used for flavoring is typically not the primary coagulant, since a concentration of acid high enough to induce coagulation would produce an unpleasant flavor and texture. A sour taste in tofu and a slight cloudiness in the liquid around are an indication of [[bacteria]]l growth and spoilage.
  
 
==Varieties==
 
==Varieties==
There is a wide variety of tofu available in 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.
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Many varieties of tofu are available in both Western and Eastern markets. Tofu products can be categorized either as ''fresh tofu,'' which is produced directly from [[soy milk]], or as ''processed tofu,'' which is produced from fresh tofu. Tofu production also creates important side products which are used in various cuisines. A byproduct of the process is [[Okara (food)|soy pulp]] (also called ''okara'' in [[Japanese language|Japanese]]).
  
 
===Fresh tofu===
 
===Fresh tofu===
Depending on the amount of water that is extracted from the tofu curds, fresh tofu can be divided into three main varieties.
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There are three main varieties of fresh tofu, depending on the amount of water that is extracted from the tofu curds:
 
[[Image:TofuWithSoySauceAndCarrot.jpg|thumb|280px|Silken tofu with soy sauce and a decorative carrot slice]]
 
[[Image:TofuWithSoySauceAndCarrot.jpg|thumb|280px|Silken tofu with soy sauce and a decorative carrot slice]]
* '''Soft/silken tofu''' ({{lang|zh|嫩豆腐}} or {{lang|zh|滑豆腐}}, ''nèn dòufǔ'' or ''huá dòufǔ'', in [[Chinese language|Chinese]], lit. "soft tofu" or "smooth tofu"; {{lang|ja|絹漉し豆腐}}, ''kinugoshi tōfu'' in [[Japanese language|Japanese]], lit. "silk-filtered tofu"; {{lang|ko|순두부}}, {{lang|ko|純豆腐}}, ''sundubu'' in [[Korean language|Korean]], lit. "pure tofu"): This undrained tofu contains the highest moisture content of all fresh tofus.<ref name=WilliamAoyagi_3>{{Harvnb|Shurtleff|Aoyagi|2000}}.</ref> Its texture can be described as similar to that of very fine [[custard]]. In Japan and Korea, traditional soft tofu is made with [[Sea water|seawater]].<ref>{{cite web|url=http://www.nytimes.com/2005/01/05/dining/05TOFU.html?ex=1262667600&en=a4616d3be9711156&ei=5088&partner=rssnyt|title=Artisanal, Creamy . . . Tofu?|publisher=New York Times|author=Julia Moskin|date=2005|accessdate=2008-01-05}}</ref><ref>{{cite web|url=http://www.foodproductiondaily.com/news/ng.asp?id=28874-new-tofu-production|title=New tofu production method|publisher=FoodProductionDaily|accessdate=2008-01-05}}</ref><ref>{{cite web|url=http://www.japanfs.org/en/column/a17.html|title=Deep Seawater Business To Develop Local Economies|publisher=Japan for sustainability|accessdate=2008-01-05}}</ref><ref>{{cite web|url=http://www.gntour.go.kr/english/CMSView.do?pid=1288|title=Chodang Bean Curd Village|publisher=Gangneung-city Tour|accessdate=2008-01-05}}</ref><ref>
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* '''Soft/silken tofu''' ({{lang|zh|嫩豆腐}} or {{lang|zh|滑豆腐}}, ''nèn dòufǔ'' or ''huá dòufǔ'', in [[Chinese language|Chinese]], lit. "soft tofu" or "smooth tofu"; {{lang|ja|絹漉し豆腐}}, ''kinugoshi tōfu'' in [[Japanese language|Japanese]], lit. "silk-filtered tofu"; {{lang|ko|순두부}}, {{lang|ko|純豆腐}}, ''sundubu'' in [[Korean language|Korean]], lit. "pure tofu"): This undrained tofu contains the highest moisture content of all fresh tofus.<ref>William Shurtleff and Akiko Aoyagi, ''The Book of Tofu & Miso'' (Berkeley, CA: Ten Speed Press, 2000).</ref> Its texture can be described as similar to that of very fine [[custard]]. In Japan and Korea, traditional soft tofu is made with [[Sea water|seawater]].<ref>[http://www.foodproductiondaily.com/news/ng.asp?id=28874-new-tofu-production New tofu production method]. ''Food Production Daily''. Retrieved June 27, 2008.</ref><ref>[http://www.japanfs.org/en/column/a17.html Deep Seawater Business To Develop Local Economies] ''Japan for Sustainability''. Retrieved June 27, 2008.</ref> ''Douhua'' ({{lang|zh|豆花}}, ''dòu huā'' or {{lang|zh|豆腐花}}, ''dòufǔ huā'' in Chinese), or ''tofu brain'' ({{lang|zh|豆腐腦}} or {{lang|zh|豆腐脑}}, ''dòufǔ 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. ''Edamame tofu'' is a Japanese variety of ''kinugoshi tōfu'' made from ''edamame'' (fresh green soybeans); it is pale green in color and often studded with whole ''edamame''.
{{cite web|url=http://english.tour2korea.com/03Sightseeing/DestinationsByThemes/Depth04.asp?sight=Sightseeing&sightseeing_id=430&ADDRESS_1=15741&ADDRESS_2=14104&ThemeCode=Sightseeing_13&kosm=m3_2 |title=Chodang Sundubu (watery tofu) Village|publisher=Tour2Korea|accessdate=2008-01-05}}</ref> ''[[Douhua]]'' ({{lang|zh|豆花}}, ''dòu huā'' or {{lang|zh|豆腐花}}, ''dòufǔ huā'' in Chinese), or ''tofu brain'' ({{lang|zh|豆腐腦}} or {{lang|zh|豆腐脑}}, ''dòufǔ 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. ''Edamame tofu'' is a Japanese variety of ''kinugoshi tōfu'' made from ''edamame'' (fresh green soybeans); it is pale green in color and often studded with whole ''edamame''.
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* '''Asian firm tofu''' (simply called {{lang|zh|豆腐}} ''lǎo dòufǔ'' in Chinese; {{lang|ja|木綿豆腐}}, ''momendōfu'' in Japanese, lit. "cotton tofu"): Although drained and pressed, this form of fresh tofu still contains a considerable amount of moisture. It has the firmness of raw meat, but bounces back readily when pressed. The texture is similar to a firm custard. The skin retains the pattern of the muslin used to drain it. Firm tofu can be picked up easily with [[chopsticks]].<ref>William Shurtleff and Akiko Aoyagi, ''Volume IV, The History of Traditional Non-Fermented Soyfoods, Chapter 36'' (2008) [http://www.soyinfocenter.com/HSS/tofu1.php History of Tofu]. Retrieved June 28, 2008.</ref>
* '''Asian firm tofu''' (simply called {{lang|zh|豆腐}} ''lǎo dòufǔ''{{Fact|date=April 2008}} in Chinese; {{lang|ja|木綿豆腐}}, ''momendōfu'' in [[Japanese language|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]].<ref name=WilliamAoyagi_1>{{Harvnb|Shurtleff|Aoyagi|2008}}, Volume IV, The History of Traditional Non-Fermented Soyfoods, Chapter 36: {{cite web|title=History of Tofu|url=http://www.soyinfocenter.com/HSS/tofu1.php}}</ref><ref name=WilliamAoyagi_3/>
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* '''Western firm/dried tofu''' ({{lang|zh|豆乾}}, ''dòu gān'' in Chinese, lit. "dry tofu"): An extra firm variety with the least amount of moisture, it has the firmness of fully cooked meat, and a somewhat rubbery feel. The skin of retains the pattern of the muslin used to drain and press it. When milled and re-formed after pressin it sometimes lacks the skin with its cloth patterning. One variety pressed flat and sliced into long strings smaller than 2&nbsp;mm × 2&nbsp;mm, called shredded dried tofu ({{lang|zh|豆乾絲}}, ''dòu gān sī'' in Chinese, or simply {{lang|zh|乾絲}}, ''gān sī''), looks like loose cooked [[noodle]]s, and can be served cold, stir-fried, or similar in style to Japanese ''aburaage.''<ref>[http://www.flickr.com/photos/initial_tai/388562141/ A photo of ''aburaage'']. Retrieved June 21, 2008.</ref>
* '''Western firm/dried tofu''' ({{lang|zh|豆乾}}, ''dòu 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 is pressed especially flat and sliced into long strings with a cross section smaller than 2&nbsp;mm × 2&nbsp;mm. Shredded dried tofu ({{lang|zh|豆乾絲}}, ''dòu gān sī'' in Chinese, or simply {{lang|zh|乾絲}}, ''gān sī''), which looks like loose cooked [[noodle]]s, and can be served cold, stir-fried, or similar in style to Japanese ''[[aburaage]]''.<ref>{{cite web|url=http://www.flickr.com/photos/initial_tai/388562141/|title=A photo}}</ref><ref name=WilliamAoyagi_1/>
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Fresh tofu is usually sold completely immersed in water to maintain its moisture.
Fresh tofu is usually sold completely immersed in water to maintain its moisture content.<ref name=TofuDao>{{Harvnb|Morii|Isshi|2004}}.</ref>
 
  
===Processed tofu===
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===Processed===
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 flavors.<ref name=WilliamAoyagi_2>{{Harvnb|Shurtleff|Aoyagi|2008}}. Volume V, The History of Traditional Fermented Soyfoods, Chapter 44: {{cite web|title=History of Fermented Tofu|url=http://www.soyinfocenter.com/HSS/fermented_tofu1.php}}</ref>
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Many forms of processed tofus exist. Some of these processing techniques probably originated 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 flavors.
  
 
====Fermented====
 
====Fermented====
*'''[[Pickled tofu]]''' ({{lang|zh|[[wiktionary:豆|豆]][[wiktionary:腐|腐]][[wiktionary:乳|乳]]}} in Chinese, [[pinyin]]: ''dòufǔ rǔ'', lit. "tofu dairy," or {{lang|zh|[[wiktionary:腐|腐]][[wiktionary:乳|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.<ref name=WilliamAoyagi_2 /> The dry fermented tofu is then soaked in salt water, Chinese wine, vinegar, and minced [[chile pepper|chiles]], or a unique mixture of whole rice, bean paste, and soybeans. In the case of red pickled tofu ({{lang|zh|[[wiktionary:紅|紅]][[wiktionary:豆|豆]][[wiktionary:腐|腐]][[wiktionary:乳|乳]]}} in Chinese, Pinyin: hóng dòufǔ rǔ), [[red yeast rice]] (cultivated with ''[[Monascus purpureus]]'') is added for color.<ref>The Hwang Ryh Shang Company of Taiwan, a major producer of pickled tofu, mislabels this ingredient as "red date" ([[jujube]]) on the English-language list of ingredients on its product labels, although the Chinese list of ingredients on the same product lists 紅糟 (literally "red [[Lees (fermentation)|lees]]", i.e. red yeast rice).</ref>
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*'''Pickled tofu''' ({{lang|zh|豆腐乳}} in Chinese, [[pinyin]]: ''dòufǔ rǔ'', lit. "tofu dairy," or {{lang|zh|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.<ref>Shurtleff and Aoyagi, Volume V, ''The History of Traditional Fermented Soyfoods, Chapter 44: History of Fermented Tofu'' (2008). </ref> The dry fermented tofu is then soaked in salt water, Chinese wine, vinegar, and minced [[chile pepper|chiles]], or a unique mixture of whole rice, bean paste, and soybeans. In the case of red pickled tofu ({{lang|zh|紅豆腐乳}} in Chinese, Pinyin: hóng dòufǔ rǔ), red yeast rice (cultivated with ''Monascus purpureus'') is added for color.<ref>The Hwang Ryh Shang Company of Taiwan, a major producer of pickled tofu, mislabels this ingredient as "red date" ([[jujube]]) on the English-language list of ingredients on its product labels, although the Chinese list of ingredients on the same product lists 紅糟 (literally "red lees," (red yeast rice).</ref>
*'''[[Stinky tofu]]''' ({{lang|zh|[[wiktionary:臭|臭]][[wiktionary:豆|豆]][[wiktionary:腐|腐]]}} in Chinese, Pinyin: ''chòu dòufǔ''): A soft tofu that has been fermented in a unique vegetable and fish brine.<ref name=WilliamAoyagi_2/>  The blocks of tofu smell strongly of certain pungent cheeses, and are described by many as rotten and fecal.  Despite its strong odor, the flavor and texture 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.
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*'''[[Stinky tofu]]''' ({{lang|zh|臭豆腐}} in Chinese, Pinyin: ''chòu dòufǔ''): 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, but the flavor and texture of stinky tofu is appreciated by aficionados, who describe it as delightful. 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.
  
 
====Flavored====
 
====Flavored====
[[Image:AlmondTofu.jpg|thumb|250px|right|Almond "tofu," which is not made of [[soy milk]] but rather from [[gelatin]] or [[agar]]ose]]
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Flavors can be mixed directly into the curdling soy milk while tofu is being produced.
[[Image:PHOT0070.JPG|thumb|250px|right|Chili-peppered egg tofu from Ipoh, Malaysia.]]
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*'''Sweet''': Common sweet dessert tofus include peanut tofu ({{lang|zh|落花生豆腐}}, luòhuāshēng dòufǔ in Chinese and ''jimami-dōfu'' in Japanese), almond tofu ({{lang|zh|杏仁豆腐}}, xìngrén dòufǔ in Chinese; {{lang|ja|杏仁豆腐}}, annindōfu in Japanese), mango tofu, and coconut tofu. In order to produce these forms of tofu, sugar, fruit acids, and flavorants are mixed into soy milk prior to curdling. Most sweet tofus have the texture of silken tofu and are served cold.
Flavors can be mixed directly into curdling soy milk while the tofu is being produced.
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* 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.
*'''Sweet''': Common sweet dessert tofus include peanut tofu ({{lang|zh|落花生豆腐}}, luòhuāshēng dòufǔ in Chinese and ''jimami-dōfu'' in Japanese), almond tofu ({{lang|zh|杏仁豆腐}}, xìngrén dòufǔ in Chinese; {{lang|ja|杏仁豆腐}}, annindōfu in Japanese), mango tofu, and coconut tofu. In order to produce these forms of tofu, sugar, fruit acids, and flavorants are mixed into soy milk prior to curdling. Most sweet tofus have the texture of silken tofu and are served cold.
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*'''Savory''': Egg tofu (Japanese: {{lang|ja|玉子豆腐}}, {{lang|ja|卵豆腐}}, tamagodōfu) (Chinese: {{lang|zh|蛋豆腐}}, dàn dòufǔ; often called {{lang|zh|日本豆腐}}, rìbĕn dòufǔ, lit. "Japan bean curd") is the main type of savory flavored 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 color that can be attributed to the addition of egg and, occasionally, food coloring. This tofu has a fuller texture and flavor than silken tofu, which can be attributed to the presence of egg fat and protein.
** 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 (Japanese: {{lang|ja|玉子豆腐}}, {{lang|ja|卵豆腐}}, tamagodōfu) (Chinese: {{lang|zh|蛋豆腐}}, dàn dòufǔ; often called {{lang|zh|日本豆腐}}, rìbĕn dòufǔ, lit. "Japan bean curd") is the main type of savory flavored 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 color that can be attributed to the addition of egg and, occasionally, food coloring. This tofu has a fuller texture and flavor than silken tofu, which can be attributed to the presence of egg fat and protein.
 
  
 
====Fried====
 
====Fried====
*With the exception of the softest tofus, all forms of tofu could be fried. Thin and soft varieties of tofu are [[Deep frying|deep fried]] in oil until they are light and airy in their core ([[wiktionary:豆|豆]][[wiktionary:泡|泡]] in Chinese, ''dòupào'', lit. "bean bubble," describing the shape of the fried tofu as a bubble).
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*With the exception of the softest tofus, all forms of tofu can be fried. Thin and soft varieties of tofu are [[Deep frying|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 ([[wikt:炸|炸]][[wikt:豆腐|豆腐]] in Chinese, ''zhà dòufǔ'', 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 ''[[Buddha's delight|luohan zhai]]''.
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*Tofus with lower moisture content, such as firm Asian and dry tofus, are cut into bite-sized cubes or triangles and deep fried until they develop a golden-brown, crispy surface (炸豆腐 in Chinese, ''zhà dòufǔ'', 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, and are included as part of the vegetarian dish called "Buddha's delight" ''(luohan zhai)''.
  
 
====Frozen====
 
====Frozen====
 
[[Image:Dong Dou Fu (tofu).jpg|thumb|250px|Thawed and sliced frozen tofu]]
 
[[Image:Dong Dou Fu (tofu).jpg|thumb|250px|Thawed and sliced frozen tofu]]
* '''Thousand layer tofu''' ({{lang|zh|[[wiktionary:千|千]][[wiktionary:葉|葉]][[wiktionary:豆|豆]][[wiktionary:腐|腐]], [[wiktionary:凍|凍]][[wiktionary:豆|豆]][[wiktionary:腐|腐]] or [[wiktionary:冰|冰]][[wiktionary:豆|豆]][[wiktionary:腐|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 sometimes squeezed of moisture prior to use.<ref name=TofuDao/>
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* '''Thousand layer tofu''' ({{lang|zh|千葉豆腐, 凍豆腐 or 冰豆腐}} in Chinese, lit. "thousand layer tofu" or "frozen tofu"): When tofu is frozen, the large ice crystals that develop within it form large cavities that appear to be layered (pseudostratified). The frozen tofu takes on a yellowish hue during the freezing process. “Thousand-layer tofu” is commonly made at home by freezing Asian soft tofu, though it is also commercially sold as a regional specialty in parts of Taiwan. This tofu is defrosted and sometimes squeezed of moisture prior to use.<ref name=Morii/>  
* '''Koyadofu''' (''kōyadōfu'', {{lang|ja|[[wiktionary:高|高]][[wiktionary:野|野]][[wiktionary:豆|豆]][[wiktionary:腐|腐]]}} in Japanese): The name comes from [[Mount Koya]], a center of [[Japanese Buddhism]] famed for its ''[[Buddhist cuisine|shōjin ryōri]]'', or traditional Buddhist vegetarian cuisine. It is sold in [[freeze drying|freeze-dried]] blocks or cubes in Japanese markets. It must be soaked in water before eating, and is typically simmered in [[dashi]], [[sake]] or [[mirin]] and [[soy sauce]]. In ''shōjin ryōri'', vegetarian ''kombu dashi'', made from seaweed, is used. When prepared in the usual manner, it has a spongy texture and mild sweet and savory flavor. A similar form of freeze-dried tofu, in smaller pieces, is found in instant soups (such as [[miso soup]]), in which the toppings are freeze-dried and stored in sealed pouches.
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* '''Koyadofu''' (''kōyadōfu'', {{lang|ja|高野豆腐}} in Japanese): The name comes from Mount Koya, a center of [[Japanese Buddhism]] famed for its ''[[Buddhist cuisine|shōjin ryōri]],'' or traditional Buddhist vegetarian cuisine. It is sold in [[freeze drying|freeze-dried]] blocks or cubes in Japanese markets. It must be soaked in water before eating, and is typically simmered in ''dashi,'' [[sake]] or ''mirin'' and [[soy sauce]]. In ''shōjin ryōri,'' vegetarian ''kombu dashi,'' made from seaweed, is used. When prepared in the usual manner, it has a spongy texture and mild sweet, savory flavor. A similar form is found in instant soups (such as [[miso|miso soup]]), in which the toppings are freeze-dried and stored in sealed pouches.
  
===Byproducts of tofu production===
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===By-products 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''.
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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 solids left over from pressing soy milk are called ''okara.''
  
 
==== Tofu skin ====
 
==== Tofu skin ====
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.<ref name=TofuDao/>  The films are collected and dried into yellowish sheets known as '''soy milk skin''' ({{lang|zh|腐皮}}, ''fǔ pí'' in Chinese; {{lang|ja|湯葉}}, ''yuba'' in Japanese). Its approximate composition is : 50–55% protein, 24–26% lipids (fat), 12% carbohydrate, 3% ash, and 9% moisture.<ref>{{cite web|url=http://www.thesoydaily.com/SFC/NFsoyfoods38.asp|publisher= The Soy Daily|title=Broken link}} Not retrieved on [[5 January]] [[2008]].</ref>
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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 '''soy milk skin''' ({{lang|zh|腐皮}}, ''fǔ pí'' in Chinese; {{lang|ja|湯葉}}, ''yuba'' in Japanese). Its approximate composition is: 50–55 percent protein, 24–26 percent lipids (fat), 12 percent carbohydrate, 3 percent ash, and 9 percent moisture.
 
 
The skin can also be bunched up to stick form and dried into something known as "tofu bamboo" ({{lang|zh|腐竹}}, ''fǔ zhú'' in Chinese; ''phù chúc'' in Vietnamese; ''kusatake'', Japanese), or myriad 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.
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The skin can also be bunched up in stick form and dried into something known as "tofu bamboo" ({{lang|zh|腐竹}}, ''fǔ zhú'' in Chinese; ''phù chúc'' in Vietnamese; ''kusatake,'' Japanese). Tofu skin, with its soft yet rubbery texture, is folded or shaped into different forms and cooked further to imitate meat in vegetarian cuisine.
  
 
====Okara====
 
====Okara====
[[Okara (food)|Okara]] ({{lang|zh|雪花菜}}, ''xuě huā caì'', lit. "snowflake vegetable"; {{lang|zh|豆腐渣}}, ''dòufǔ zhā'', lit. "tofu sediment/residue"; ''kongbiji'', 콩비지 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.<ref name=TofuDao/>  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 [[Veggie burger|vegetarian burgers]] produced in many western nations.
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[[Okara (food)|Okara]] ({{lang|zh|雪花菜}}, ''xuě huā caì,'' lit. "snowflake vegetable"; {{lang|zh|豆腐渣}}, ''dòufǔ zhā,'' lit. "tofu sediment/residue"; ''kongbiji,'' 콩비지 in Korean), sometimes known in the west as soy pulp, is the fiber, 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.
  
 
===Tofu made from other legumes and grains===
 
===Tofu made from other legumes and grains===
[[Image:IMG 1416.JPG|thumb|right|270px|''To hpu'' (Burmese tofu), in two forms: fresh and fritters]]
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* '''Black bean tofu''' ({{lang|zh|黑豆花}}): A type of tofu made from plain black beans and soybeans, which is usually made into ''dòuhuā'' ({{lang|zh|[[wiktionary:豆|豆]][[wiktionary:花|花]]}}) rather than firm or dry tofu. The texture of black bean tofu is slightly more gelatinous than regular tofu flower, and the color is grayish. This type of tofu is eaten for the earthy "black bean taste."
 
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* '''[[Burmese tofu]]''' (''to hpu'' in [[Burmese language|Burmese]]): A type of tofu made from gram ''(besan)'' or chickpea ''(chana dal)'' flour instead of soybeans; the Shan variety uses yellow split pea flour instead. Both types are yellow in color and generally found only in [[Myanmar]], though the Burman variety is also available in some overseas restaurants serving [[Cuisine of Myanmar|Burmese cuisine]].<ref>[http://www.netcooks.com/recipes/Salads/Burmese-Style.Tofu.html Burmese tofu recipe] ''Netcooks.com''. Retrieved June 21, 2008.</ref>
* '''Black bean tofu''' ({{lang|zh|黑豆花}}): A type of tofu made from plain black beans<!--Are these black soybeans or the kind of black beans that Mexicans and Brazilians eat? probably the former, though I'm not sure—> and soybeans, which is usually made into ''dòuhuā'' ({{lang|zh|[[wiktionary:豆|豆]][[wiktionary:花|花]]}}) rather than firm or dry tofu. The texture of black bean tofu is slightly more gelatinous than regular tofu flower and the color is greyish in tone. This type of tofu is eaten for the earthy "black bean taste."
 
* '''[[Burmese tofu]]''' (''to hpu'' in [[Burmese language|Burmese]]): A type of tofu made from ''[[Gram flour|besan]]'' ([[Chickpea|''chana dal]]'') flour instead of soybeans; the [[Shan]] variety uses [[pigeon pea|yellow split pea]] flour instead. Both types are yellow in color and generally found only in [[Myanmar]], though the [[Bamar|Burman]] variety is also available in some overseas restaurants serving [[Cuisine of Myanmar|Burmese cuisine]].<ref>{{cite web|url=http://www.netcooks.com/recipes/Salads/Burmese-Style.Tofu.html|title=Burmese tofu recipe}}</ref>
 
 
 
:''To hpu'' may be fried as fritters cut in rectangular or triangular shapes; the latter fried twice, hence the name ''hnapyan gyaw'' (literally "twice fried"), is the common form in the [[Shan States]]. ''To hpu nway'', creamy and soft before it sets, is also popular served hot on its own or with [[rice noodles]]. ''To hpu gyauk'', which are deep fried, thin, and crispy, are similar to [[Prawn cracker|prawn]] or fish crackers.
 
  
:Rice tofu, called ''hsan to hpu'' (or ''hsan ta hpo'' in Shan regions) is made from rice flour (called ''hsan hmont'' or ''mont hmont'') and is white in color, with the same consistency as yellow Burmese tofu when set.  It is eaten as a salad in the same manner as yellow tofu.
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:''To hpu'' may be fried as fritters cut in rectangular or triangular shapes; the latter fried twice, hence the name ''hnapyan gyaw'' (literally "twice fried"), is the common form in the Shan States. ''To hpu nway,'' creamy and soft before it sets, is also popular served hot on its own or with [[rice noodles]]. ''To hpu gyauk,'' which are deep fried, thin, and crispy, are similar to prawn or fish crackers.
  
<gallery>
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:Rice tofu, called ''hsan to hpu'' (or ''hsan ta hpo'' in Shan regions) is made from rice flour (called ''hsan hmont'' or ''mont hmont'') and is white in color, with the same consistency as yellow Burmese tofu when set. It is eaten as a salad in the same manner as yellow tofu.
Image:IMG tofufritters.JPG|''To hpu gyaw'' (Burmese tofu fritters)
 
Image:IMG 0195.JPG|''To hpu nway'' (warm Burmese tofu) and ''to hpu gyaw'' (Burmese tofu fritters) salad
 
Image:IMG tofucrackers.JPG|''To hpu gyauk'' (Burmese tofu crackers, ready for deep frying)
 
Image:IMG 0068.JPG|''Hsan ta hpo'' (Burmese rice tofu)  salad
 
</gallery>
 
  
 
==Preparation==
 
==Preparation==
Tofu has very little flavor or smell on its own.  As such, tofu can be prepared either in savory or sweet dishes, acting as a canvas for presenting the flavors of the other ingredients used.
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Tofu has very little flavor or smell of its own and can be prepared either in savory or sweet dishes, acting as a complement to the flavors of the other ingredients used. In Asian cuisine, tofu is served raw, stewed, stir-fried, in soup, cooked in sauce, or stuffed with fillings. The light, greenish "bean" smell of tofu is much enjoyed in East Asian cuisines and fresh tofu is often eaten plain or simply flavored.
  
===Eastern methods===
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In [[Japan]], a common lunch in the summer months is ''hiyayakko'' ({{lang|ja|冷奴}}), silken or firm Asian tofu served with freshly grated [[ginger]], [[scallion]]s, ''[[katsuobushi]]'' (dried salmon) shavings and [[soy sauce]]. In many parts of [[China]], fresh tofu is similarly eaten with soy sauce, [[century egg]]s ({{lang|ja|皮蛋}}), and [[sesame seed]] oil.
In Asian cooking, tofu is eaten in myriad ways, including raw, stewed, stir-fried, in soup, cooked in sauce, or stuffed with fillings.
 
  
====Lightly flavored====
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[[Image:Dofuhua-lamma.jpg|thumb|right|240px|''Dòuhuā'' ({{lang|zh|豆花}}), is a soft tofu dish. The fresh tofu is served warm and dressed with sweet syrup. [[Lamma Island]], [[Hong Kong]].]]
The light greenish "bean" smell of tofu is much enjoyed in East Asian cuisines and fresh tofu is often eaten plain or simply flavored.
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In [[Chinese cuisine]], ''[[Douhua|Dòuhuā]]'' ({{lang|zh|豆花}}) is served with toppings like boiled [[peanut]]s, [[azuki bean]]s, cooked [[oatmeal]], [[tapioca]], [[mung bean]]s and a syrup flavored with [[ginger]] or [[almond]]. During the summer, ''dòuhuā'' is served with crushed ice; in the winter, it is served warm.<ref name=bookoftofu/>
  
In [[Japan]], a common lunch in the summer months is ''[[hiyayakko]]'' ({{lang|ja|[[wiktionary:冷|冷]][[wiktionary:奴|奴]]}}), silken or firm Asian tofu served with freshly grated [[ginger]], [[scallion]]s, and [[soy sauce]].  In many parts of [[China]], fresh tofu is similarly eaten with soy sauce or further flavored with ''[[katsuobushi]]'' shavings, [[century egg]]s ({{lang|ja|[[wiktionary:皮|皮]][[wiktionary:蛋|蛋]]}}), and [[sesame seed]] oil.
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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 Japanese ''hiyayakko,'' are also enjoyed.
 
 
[[Image:Dofuhua-lamma.jpg|thumb|right|240px|''Dòuhuā'' ({{lang|zh|豆花}}), is a soft tofu dish.  The fresh tofu is served warm and here dressed with sweet syrup.  [[Lamma Island]], [[Hong Kong]].]]
 
In [[Chinese cuisine]], ''[[Douhua|Dòuhuā]]'' ({{lang|zh|[[wiktionary:豆|豆]][[wiktionary:花|花]]}}) is served with toppings like boiled [[peanut]]s, [[azuki bean]]s, cooked [[oatmeal]], [[tapioca]], [[mung bean]]s and a syrup flavored with [[ginger]] or [[almond]].  During the summer, ''dòuhuā'' is served with crushed ice; in the winter, it is served warm.<ref name=tofuBook> {{Harvnb|Shurtleff|Aoyagi|2005}}.</ref>
 
 
 
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 ''hiyayakko''are also enjoyed.
 
  
 
In the [[Philippines]], the sweet delicacy [[taho]] is made of fresh tofu with brown sugar syrup and [[sago]].
 
In the [[Philippines]], the sweet delicacy [[taho]] is made of fresh tofu with brown sugar syrup and [[sago]].
  
In Vietnam, ''dòuhuā'' is pronounced ''đậu hủ''This variety of soft tofu is made and carried around in an earthenware jar. It is served by being scooped into a bowl with a very shallow and flat spoon, and eaten with either powdered sugar and lime juice or with a ginger-flavored syrup. It is generally eaten hot, even during summer.
+
In Vietnam, ''dòuhuā'' is pronounced ''đậu hủ.'' This variety of soft tofu is made and carried around in an earthenware jar. It is scooped into a bowl with a shallow, flat spoon, and is served with either powdered sugar and lime juice, or with a ginger-flavored syrup. It is generally eaten hot, even during summer.
  
 
====Fried====
 
====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 [[surimi|fish paste]] or cooked in soups.<ref name=tofuBook/>  In Japan, cubes of lightly coated and fried tofu topped with a [[kombu]] [[dashi]]-based sauce are called ''[[Agedashi tofu|agedashi-dofu]]'' ({{lang|ja|揚げ出し豆腐}}). Soft tofu that has been thinly sliced and deep fried, known as ''aburage'' in Japan, is commonly [[blanching|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'' ({{lang|ja|稲荷寿司}}) .
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A common cooking technique in many parts of East and Southeast Asia involves deep frying tofu in [[vegetable oil]], [[sunflower]] oil, or [[canola]] oil. 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 ''(surimi)'' or cooked in soups.<ref name=bookoftofu/>  In Japan, cubes of lightly coated and fried tofu topped with a [[kombu]] [[dashi]]-based sauce are called ''[[Agedashi tofu|agedashi-dofu]]'' ({{lang|ja|揚げ出し豆腐}}). Soft tofu that has been thinly sliced and deep fried, known as ''aburage'' in Japan, is commonly [[blanching|blanched]], seasoned with [[soy sauce]] and [[mirin]] and served in dishes such as ''kitsune udon''. ''Aburage'' is sometimes soaked in  a sweet syrup and cut open to form a pocket; stuffed with [[sushi]] rice, this dish is called ''inarizushi'' ({{lang|ja|稲荷寿司}}) .
  
 
====Soups, stews, and braised dishes====
 
====Soups, stews, and braised dishes====
[[Image:Yudofu.jpg|thumb|''Yudofu'', or tofu in hot water.]]
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[[Image:Yudofu.jpg|thumb|Tofu in hot water.]]
  
A rather famous hot [[Szechuan cuisine|Sichuan]] preparation using firm Asian tofu is ''[[mapo tofu|mápó dòufu]]'' ({{lang|zh|[[wiktionary:麻|麻]][[wiktionary:婆|婆]][[wiktionary:豆|豆]][[wiktionary:腐|腐]]}}). This involves braised tofu in a [[beef]], chili, and a fermented bean paste sauce. In the [[Shanghai]] region it is called ''málà dòufǔ'' ({{lang|zh|[[wiktionary:麻|麻]][[wiktionary:辣|辣]][[wiktionary:豆|豆]][[wiktionary:腐|腐]]}}).
+
A well-known hot [[Szechuan cuisine|Sichuan]] preparation using firm Asian tofu is ''mápó dòufu'' ({{lang|zh|麻婆豆腐}}). Tofu and beef are braised in a sauce of chili, ginger and fermented bean paste. In the [[Shanghai]] region it is called ''málà dòufǔ'' ({{lang|zh|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" ({{lang|zh|五香豆腐}}) or "soy sauce stewed tofu" ({{lang|zh|鹵水豆腐}}). Dried tofu is typically served thinly sliced with chopped [[Scallion|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.<ref name=tofuBook/>
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Dried tofu is usually not eaten raw, but stewed in a mixture of soy sauce and spices. Some types of dried tofu are pre-seasoned with special blends of spices, so that the tofu may either be called "five spice tofu" ({{lang|zh|五香豆腐}}) or "soy sauce stewed tofu" ({{lang|zh|鹵水豆腐}}). Dried tofu is typically served thinly sliced with chopped [[Scallion|green onions]] or with slices of meat for added flavor. Most dried tofu is sold after it has been fried or stewed by tofu vendors.<ref name=bookoftofu/>
 +
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.
  
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.
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Tofu bamboos are often used in [[Lamb (meat)|lamb]] stew or in a [[dessert]] [[soup]]. Tofu skins are often used as wrappers in [[dim sum]]. Freeze-dried tofu and frozen tofu are rehydrated and enjoyed in savory soups. These products are often taken along on journeys; a small bag of dried tofu can provide protein for many days.
  
Tofu bamboos are often used in [[Lamb (meat)|lamb]] stew or in a [[dessert]] [[soup]].  Tofu skins are often used as wrappers in [[dim sum]].  Freeze-dried tofu and frozen tofu are rehydrated and enjoyed in savory soups.  These products are often taken along on camping trips since a small bag of these dried tofu can provide protein for many days.
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In Korean cuisine, soft tofu (''sundubu'' in Korean) is used to make a thick soup called ''sundubu jjigae'' ({{lang|ko|순두부 찌개}}).
 
 
In Korean cuisine, soft tofu (''sundubu'' in Korean) is used to make a thick soup called [[sundubu jjigae]] ({{lang|ko|순두부 찌개}}).
 
  
 
====As flavoring====
 
====As flavoring====
Pickled tofu is commonly used in small amounts together with its soaking liquid to flavor stir-fried or braised [[vegetable]] dishes (particularly [[leaf vegetable|leafy green vegetable]]s like [[Ipomoea aquatica|water spinach]]). It is often eaten directly as a [[condiment]] with rice or [[Rice congee|congee]].
+
Pickled tofu is commonly used in small amounts together with its soaking liquid to flavor stir-fried or braised [[vegetable]] dishes (particularly [[leaf vegetable|leafy green vegetable]]s like [[Ipomoea aquatica|water spinach]]). It is often eaten directly as a [[condiment]] with rice or congee.
  
 
===Western methods===
 
===Western methods===
Generally, the firmer styles of tofu are used for [[kebab]]s, mock meats, and dishes requiring a consistency that holds together, while the softer styles can be used for desserts, soups, shakes, and sauces.
+
Firm tofu can be used for [[kebab]]s, 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 (techniques to increase penetration of marinades are stabbing repeatedly with a fork or freezing and thawing prior to marinating).  Grated firm western tofu is sometimes used in conjunction with [[Textured vegetable protein|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]]).
 
 
 
Tofu has also been fused into other cuisines in the west, for instance used in Indian-style curries.
 
 
 
Tofu and soy protein can be industrially processed to match the textures and flavors to the likes of [[cheese]], [[pudding]], [[egg (food)|eggs]], [[bacon]] etc.  Tofu's texture can also be altered by [[freezing]], [[puree]]ing, 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.
 
 
 
==History==
 
Tofu originated in ancient [[China]],<ref name=Soya> ''[http://www.soya.be/history-of-tofu.php ''History of Tofu''</ref> however little else 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 B.C.E.]] by Lord [[Liu An]], a [[Han Dynasty]] prince.  Although this is possible, the paucity of concrete information about this period makes it difficult to conclusively determine whether 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.<ref name=WilliamAoyagi_1/><ref name=TofuDao />
 
 
 
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.<ref>Korean ''sundubu'' (soft tofu) is still produced in a similar manner, traditionally using seawater as a coagulant.</ref>  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.  Its technical plausibility notwithstanding, there is little evidence to prove or disprove that tofu production originated in this way.<ref name=WilliamAoyagi_1 />
 
 
 
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 [[Mongols|Mongolian]]s or [[East Indian]]s.  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.<ref name=WilliamAoyagi_1/>
 
  
===In Asia===
+
Before grilling, firm tofu is usually marinated overnight. Grated firm western tofu is sometimes used in conjunction with TVP (textured vegetable protein) as a meat substitute. Softer tofus are sometimes used as a dairy-free or low-calorie filler, or made into ice cream substitutes. Silken tofu may be used to replace [[cheese]] in certain dishes (such as lasagna) or incorporated into Indian-style curries.
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 B.C.E.]]. 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 Dynasty|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.
 
  
In China,  tofu is traditionally used as a food offering when visiting the graves of deceased relatives.  It is claimed that the spirits (or ghosts) have long lost their chins and jaws, and that only tofu is soft enough for them to eat. Before [[refrigeration]] was available in China, tofu was often only sold during the winter time, due to the tofu not spoiling in the colder weather.  During the warmer months, any leftover tofu would be spoiled if left for more than a day. Chinese war hero [[Guan Yu]] used to be a tofu maker before he enlisted in the army. Chinese martial arts expert and hero, [[Yim Wing-chun]], was a celebrated tofu maker in her village.  (Tofu as such plays a part in the 1994 movie about her life, [[Wing Chun (film)|"Wing Chun"]].)
+
Tofu and soy protein can be industrially processed to match the textures and flavors of [[cheese]], [[pudding]], [[egg (food)|eggs]], or [[bacon]]. Tofu's texture can also be altered by [[freezing]], [[puree]]ing, and [[cooking]]. In the Americas, [[Europe]], [[Australia]] and [[New Zealand]], tofu is frequently associated with [[vegetarianism]] and [[veganism]] as a source of high-quality, non-animal protein.
 
 
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]]. The earliest document of tofu in Japan shows that the dish was served as an offering at the [[Kasuga Shrine]] in [[Nara, Nara|Nara]] in 1183<ref>''A taste of Japan'', Donald Richie, [[Kodansha]], [[2001]], ISBN 4770017073</ref>. The book ''[[Tofu Hyakuchin]]'' ({{lang|ja|豆腐百珍}}), published in the [[Edo period]], lists 100 recipes for cooking tofu.
 
 
 
The rise in acceptance of tofu likely coincided with that of [[Buddhism]] as it is an important source of proteins in the religion's vegetarian diet.<ref name=TofuDao />  Since then, tofu has become a [[Staple food|staple]] in many countries, including [[Vietnam]], [[Thailand]], and [[Korea]], with subtle regional variations in production methods, texture, flavor, and usage.
 
 
 
Tofu is so highly esteemed in Korean culture that the menus of many Korean restaurants are based almost entirely on tofu, including some which feature only ''[[sundubu jjigae]]'' (a stew made with soft tofu) and ''[[gochujang]]'' (red chili paste).{{Fact|date=December 2007}}
 
 
 
===In the West===
 
Tofu was not well known to most Westerners before the middle of the [[20th century]]. With increased cultural contact and an interest in [[vegetarianism]], tofu has become almost universally known in the west.
 
However, due largely to ongoing attempts to use tofu as a substitute for traditional western meat-foods, with imperfect success, it is often regarded as unappetizing, and is often the butt of jokes, much like the product [[SPAM_(food)|Spam]]. This is not to say that there are not significant numbers of westerners with a taste for tofu, though. For example, several types of preflavored tofu are sold at major supermarket chains, such as [[Albert Heijn]] in the Netherlands. Grocery stores in urban areas of the United States generally stock many varieties of tofu as well.
 
  
 
== Nutrition and health information ==
 
== Nutrition and health information ==
Tofu is low in [[calorie]]s, contains beneficial amounts of [[iron]] (especially important for women of child bearing age) and has no [[cholesterol]] (a risk factor for heart disease).<ref>{{Harvnb|Grundy|Cleeman|Daniels|Donato|2005}}.</ref>  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).
+
Tofu is low in [[calorie]]s, 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). Tofu is relatively high in [[protein]], about 10.7 percent for firm tofu and 5.3 percent for soft "silken" tofu with about 2 percent and 1 percent fat respectively as a percentage of weight.<ref>Catharina Y. W. Ang, KeShun Liu, and Yao-Wen Huang, ''Asian Foods: Science & Technology'' (Lancaster, PA: Technomic Publishing Co., 1999).</ref>
 
 
===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.<ref>{{Harvnb|Ang|Liu|Huang|1999}}.</ref>
 
 
 
In 1995, a report from the [[University of Kentucky]], financed by [http://www.solae.com/ The Solae Company] [[St. Louis, Missouri]] (the PTI division of DuPont), concluded that soy protein is correlated with significant decreases in serum cholesterol, Low Density Lipoprotein [[LDL]] (bad cholesterol) and triglyceride concentrations.<ref name="AJC">{{Harvnb|Anderson|Johnstone|Cook-Newell|1995}}.</ref> However, High Density Lipoprotein [[High density lipoprotein|HDL]] (good cholesterol) did not increase.  Soy [[phytoestrogens]] ([[isoflavones]]: genistein and daidzein) absorbed 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."<ref name="fda">{{cite web|title=Soy: Health Claims for Soy Protein, Questions About Other Components|url=http://www.fda.gov/fdac/features/2000/300_soy.html|publisher=U.S. Food and Drug Administration}}</ref> 100 grams of firm tofu, for instance, contains 11.5 grams of soy protein.<ref>FDA Consumer Magazine, May-June 2000.</ref> 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.<ref>{{Harvnb|Sacks|Lichtenstein|Van Horn|Harris|2006}}, [http://circ.ahajournals.org/cgi/content/full/113/7/1034#SEC2 section 2]. </ref>
 
 
 
===Isoflavones===
 
Soy isoflavones have not been shown to reduce post [[menopause]] [[hot flash]]es 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.<ref>{{Harvnb|Sacks|Lichtenstein|Van Horn|Harris|2006}}. See also {{cite web|last=Doheny|first=Kathleen|url=http://www.lifeclinic.com/healthnews/article_view.asp?story=530561|title=Soy Claim as Heart Helper in Dispute|publisher=HealthDay News|date=2006|accessdate=2008-01-05}}</ref>
 
 
 
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.<ref>{{Harvnb|White|Petrovitch|Ross|Masaki|2000}}.</ref> Nevertheless, this is a single study and by itself, does not show conclusively that soy isoflavones cause 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]].<ref name="fda"/>
+
Tofu contains soy [[isoflavones]], which can mimic natural human [[estrogen]]s and may have a variety of beneficial effects when eaten in sufficient quantities. Some health studies have claimed that regular consumption of tofu and soy milk alleviates symptoms of menopause, reduces the risk of osteoporosis, lowers bad cholesterol and helps prevent certain types of cancers.<ref>[http://pubs.cas.psu.edu/freepubs/pdfs/uk094.pdf Soy Protein and Soy Isoflavones] ''Penn State College of Agricultural Science''. Retrieved June 21, 2008.</ref> Other studies contradict these claims.<ref> Frank M. Sacks, et. al., [http://circ.ahajournals.org/content/113/7/1034.full#SEC2 "Soy Protein, Isoflavones, and Cardiovascular Health"] AHA Science Advisory ''Circulation'' 113 (2006): 1034-1044 Retrieved December 16, 2015.</ref> <ref> Kathleen Doheny, "Soy Claim as Heart Helper in Dispute" ''HealthDay News'', 2006. </ref>
  
 
==Sales and distribution==
 
==Sales and distribution==
In the West, tofu can be obtained in [[Asia]]n 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 House Foods America Corp, a subsidiary of Japan based company, [[House Foods]] Corp ([[ハウス食品]]).
+
In the East, tofu may be produced locally by relatively small vendors or distributed nationwide by large manufacturers. Fresh tofu is usually bought from local vendors and is sold directly from large bins or pots at [[street market]]s. Asian firm tofu and "tofu flower" are commonly sold in this manner and are usually no more than a few hours old. Tofu sold by large manufacturers often comes packaged in sealed plastic cartons or tubes, and may be, at most, two weeks old. In Chinese [[supermarket]]s, tofu can be found in many different flavors and grades of consistency.
 
 
House Foods America Corp. has tofu plants in California and New Jersey with a combined capacity of manufacturing 350,000 pieces of tofu per day.  Other major brands are [[Vitasoy]], a subsidiary of a Hong Kong based company, which also manufactures the brands Nasoya and Azumaya; and Mori-Nu (Morinaga Nutritional Foods), a subsidiary of [[Morinaga Milk Industry]] (森永乳業) of Japan, which pioneered the sale of shelf-stable, [[Tetra Pak|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 market]]s. 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. In Chinese [[supermarket]]s, tofu can be found in many different flavors and grades of consistency.
 
 
 
Most silken and flavored 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 Japan, silken tofu is made daily without preservatives and is considered unsellable if it sits unsold in the supermarket for 2 days.  Firm tofu is not eaten in Japan without frying as it's considered "crude".
 
  
==Etymology==
+
Most silken and flavored tofus are produced by large factories. In Japan, silken tofu without preservatives is made daily and must be sold within two days.  
The English word "tofu" comes from the [[Japanese language|Japanese]] ''tōfu'' ({{lang|ja|豆腐}}), ''{{Audio|Tofu.ogg|listen}}'' which itself derives from the [[Chinese language|Chinese]] ''dòufǔ'' ({{lang|zh|豆腐}} or {{lang|zh|荳腐}}).  Although in both languages the characters together translate as "bean curd," the literal meaning of the individual characters is "bean" ([[wiktionary:豆|豆]]) and "curdled" ([[wiktionary:腐|腐]]).<ref>''American Heritage Dictionary''.</ref><ref>{{cite web|url=http://www.tofu-magazine.net/newVersion/pages/etymology.html|title=Etymology|publisher=Tofu Magazine|accessdate=2008-01-05}}</ref>
 
  
==See also==
+
In the West, tofu can be obtained in [[Asia]]n markets, farmers' markets, and [[health food]] stores. Depending on its local popularity, many grocery stores also stock tofu.
{{Portal|Food|Portal.svg}}
 
 
 
* [[Tempeh]]
 
* [[Soy milk]]
 
* [[Soybean]]
 
* [[Douhua]]
 
* [[Buddhist cuisine]]
 
* [[Chinese cuisine]]
 
* [[Indonesian cuisine]]
 
* [[Japanese cuisine]]
 
* [[Korean cuisine]]
 
* [[Vegetarian cuisine]]
 
* [[Vietnamese cuisine]]
 
* [[Los Angeles Tofu Festival]]
 
  
 
==Notes==
 
==Notes==
{{reflist|2}}
+
<references/>
  
 
==References==
 
==References==
 +
*Anderson, J. W. B.M. Johnstone and  M. E. Cook-Newell, Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids. ''New England Journal of Medicine'' 333 (5) (1995): 276&ndash;282.
 +
*Ang, Catharina Y. W., KeShun Liu and Yao-Wen Huang. ''Asian Foods: Science & Technology''. Lancaster, PA: Technomic Publishing Co., 1999.
 +
*Berk, Zeki. 1992. Technology of production of edible flours and protein products from soybeans. ''FAO agricultural services bulletin'' 97. Rome: Food and Agriculture Organization of the United Nations. [http://www.fao.org/docrep/t0532e/t0532e00.htm ISBN 978-9251031186].
 +
* Grundy, Scott M., and James Cleeman, Stephen R. Daniels, Karen A. Donato, Robert H. Eckel, and Barry A. Franklin, "Diagnosis and Management of the Metabolic Syndrome. An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement." ''Circulation'' 112 (2005): 2735-2752.
 +
*Guo, Shun-Tang, and Tomotada Ono, [http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2621.2005.tb07170.x "The Role of Composition and Content of Protein Particles in Soymilk on Tofu Curding by Glucono-δ-lactone or Calcium Sulfate."] ''Journal of Food Science'' 70 (4) (2005): 258–262. Retrieved December 14, 2015.
 +
*Liu, KeShun. ''Soybeans: Chemistry, Technology, and Utilization''. Springer, 1997. ISBN 978-0834212992.
 +
*Morii, Gen ichi, Haruo Isshi. ''Tofumichi.'' Tokyo: Shinchosha, 2004. ISBN 978-4104719013. (In Japanese)
 +
*Sacks, Frank M. et al. Soy Protein, Isoflavones, and Cardiovascular Health. An American Heart Association Science Advisory for Professionals From the Nutrition Committee. ''Circulation'' 113 (7) (2006): 1034&ndash;1044.
 +
*Shurtleff, William, and Akiko Aoyagi. ''Tofu & soymilk production: a craft and technical manual,'' 3rd ed. Lafayette, CA: Soyfoods Center, 2000. ISBN 978-1928914044.
 +
*Shurtleff, William, and Akiko Aoyagi. ''The Book of Tofu: Food for Mankind''. Bookthrift Co., 1985. ISBN 978-0914398059
 +
*Shurtleff, William, and Akiko Aoyagi. ''The Book of Tofu & Miso''. Berkeley, CA: Ten Speed Press, 2001. ISBN 978-1580083584
 +
*Shurtleff, William, and Akiko Aoyagi. [http://www.soyinfocenter.com/HSS/history.php A Comprehensive History of Soy. History of Soybeans and Soyfoods Past Present and Future]. Lafayette, CA: Soyinfo Center, 2008. Retrieved December 14, 2015.
 +
*White, L. R. et al. "Brain aging and midlife tofu consumption." ''Journal of the American College of Nutrition'' 19(2) (2000): 242&ndash;255.
  
{{refbegin|2}}
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==External links==
*{{citation|last1=Anderson|first1= J. W.|last2= Johnstone|first2= B.M.|last3=Cook-Newell|first3= M.E.|journal=New England Journal of Medicine|volume=333|issue=5|title=Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids|year=1995|pages=276&ndash;282|url=http://content.nejm.org/cgi/content/full/333/5/276}}
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All links retrieved April 30, 2023.
*{{citation|editor1-last=Ang|editor1-first=Catharina Y. W.|editor2-first=KeShun|editor2-last=Liu|editor3-first=Yao-Wen|editor3-last=Huang|year=1999|url= http://www.chipsbooks.com/asianfd.htm|title= Asian Foods: Science & Technology|publisher=Technomic Publishing Co.|place= Lancaster, Pennsylvania}}
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* [http://vegetarian.about.com/od/healthnutrition/p/tofunutrition.htm Tofu Nutritional Value Information] About.com  
*{{citation|last=Berk|first= Zeki|year= 1992|title= Technology of production of edible flours and protein products from soybeans|series= FAO agricultural services bulletin|volume= 97|place=Rome|publisher= Food and Agriculture Organization of the United Nations|url=http://www.fao.org/docrep/t0532e/t0532e00.htm|isbn=978-9251031186}}.
 
*{{citation|title=Diagnosis and Management of the Metabolic Syndrome. An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement|first1=Scott M.|last1= Grundy|first2= James I.|last2= Cleeman|first3=Stephen R.|last3= Daniels|first4= Karen A.|last4= Donato|first5= Robert H.|last5=Eckel|first6= Barry A.|last6= Franklin|journal=Circulation|doi=10.1161/CIRCULATIONAHA.105.169404|volume=112|pages=2735&ndash;2752|year=2005}}
 
*{{citation|last1=Guo|first1=Shun-Tang|last2= Ono|first2=Tomotada|year=2005|title=The Role of Composition and Content of Protein Particles in Soymilk on Tofu Curding by Glucono-δ-lactone or Calcium Sulfate|journal= Journal of Food Science|volume= 70 |issue=4|pages=258–262|url=http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2621.2005.tb07170.x}}.
 
*{{citation|last=Liu|first= KeShun|year= 1997|url= http://www.springer.com/uk/home/life+sci/food+science?SGWID=3-40723-22-33274516-0|title=Soybeans: Chemistry, Technology, and Utilization|publisher=Springer| isbn=978-0834212992}}.
 
*{{citation|last1=Morii|first1=Gen ichi|first2=Haruo|last2=Isshi|year= 2004|title= Tofumichi|place=Tokyo|publisher= Shinchosha|isbn=978-4104719013}}. (In Japanese.)
 
*{{citation|first1=Frank M.|last1=Sacks|first2=Alice|last2=Lichtenstein|first3=Linda|last3=Van Horn|first4=William|last4=Harris|first5=Penny|last5=Kris-Etherton|first6=Mary|last6=Winston|title=Soy Protein, Isoflavones, and Cardiovascular Health. An American Heart Association Science Advisory for Professionals From the Nutrition Committee|journal=Circulation|year=2006|volume=113|issue=7|pages=1034&ndash;1044|doi=10.1161/CIRCULATIONAHA.106.171052}}.
 
*{{citation|last1=Shurtleff|first1= William|last2= Aoyagi|first2= Akiko|year=2000|title=Tofu & soymilk production: a craft and technical manual|edition= 3rd|place=Lafayette, California|publisher=Soyfoods Center|isbn=978-1928914044}}.
 
*{{citation|last1=Shurtleff|first1= William|last2= Aoyagi|first2= Akiko|year=2005|title= Dou fu zhi shu (The book of tofu)|publisher=Taibei Shi|isbn=978-9868131910}}. (In Chinese.)
 
*{{citation|last1=Shurtleff|first1= William|last2= Aoyagi|first2= Akiko|year=2008|title=A Comprehensive History of Soy. History of Soybeans and Soyfoods Past Present and Future|publisher=Soyinfo Center|place=Lafayette, California|url=http://www.soyinfocenter.com/HSS/history.php}}.
 
*{{citation|title=Brain aging and midlife tofu consumption|last1=White|first1= L. R.|last2= Petrovitch|first2= H.|last3=Ross|first3= G. W.|last4= Masaki|first4= K.|last5=Hardman|first5= J.|last6=Nelson|first6= J.|journal=Journal of the American College of Nutrition|year=2000|volume=19|issue=2|pages=242&ndash;255|url=http://www.jacn.org/cgi/content/full/19/2/242}}.
 
{{refend}}
 
  
==External links==
 
{{commonscat|Tofu}}
 
{{Cookbook}}
 
{{Wiktionary|tofu}}
 
  
* {{cite web|url=http://vegetarian.about.com/od/healthnutrition/p/tofunutrition.htm|title=Tofu Nutritional Value Information|publisher=About.com Vegetarian food|accessdate=2008-01-05}}
 
* {{cite web|url=http://www.abc.net.au/centralwest/stories/s398519.htm|title=Interview with Robyn Alderton regarding tofu itself and some related health benefits|publisher=ABC Central West NSW|accessdate=2008-01-05}}
 
  
 
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[[Category:Food]]
[[Category:Tofu|*]]
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[[Category:Art, music, literature, sports and leisure]]
[[Category:Chinese ingredients]]
 
[[Category:Indonesian cuisine]]
 
[[Category:Korean cuisine]]
 
[[Category:Soy products]]
 
[[Category:Japanese cuisine]]
 
[[Category:Vegan cuisine]]
 
[[Category:Japanese cuisine terms]]
 
 
 
 
 
 
 
 
 
 
 
 
{{Credits|Tofu|220298823|}}
 
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Latest revision as of 03:52, 1 May 2023

Tofu

Tofu-beijingchina.jpg
Seasoned tofu cubes in a Chinese dish

Chinese name
Traditional Chinese: 荳腐 or 豆腐
Simplified Chinese: 豆腐
Hanyu Pinyin: dòufǔ
Literal meaning: bean curd
Filipino name
Tagalog: tokwa
Japanese name
Kanji: 豆腐
Hiragana: とうふ
Korean name
Hangul: 두부
Hanja: 豆腐
Malaysian name
Malay: tauhu
Tamil name
Tamil: tahu
Thai name
Thai: tâohûː}})
Vietnamese name
Vietnamese: đậu phụ
or đậu hũ
or tàu hũ
Burmese name
Burmese: Bscript pebya.png (pebya/péprā:)
or Bscript topu.png (tofu/tiuphü:)
Khmer name
Khmer: តៅហ៊ូ
Indonesian name
Indonesian: tahu

Tofu, also tōfu (the Japanese Romaji spelling), doufu (the Chinese Pinyin spelling often used in Chinese recipes) or bean curd (the literal translation), is a food of Chinese origin, made by coagulating soy milk, and then pressing the resulting curds into blocks. There are many different varieties of tofu, including fresh tofu, tofu processed or preserved in a variety of ways, and tofu by-products such as tofu skins and soy pulp (Japanese: okara). Tofu has very little flavor or smell on its own, so it can be used either in savory or sweet dishes, and is often seasoned or marinated to suit the dish. Some tofu is made by processing non-soy products, such as almonds or black beans.

Zhongwen.png This article contains Chinese text.
Without proper rendering support, you may see question marks, boxes, or other symbols instead of Chinese characters.

Tofu originated in ancient China, but little else is known about the origins of tofu and its method of production. Tofu and its production technique were introduced into Japan in the Nara period (late eighth century), and spread to other parts of East Asia, where it has become a core ingredient of many cuisines. Tofu is low in calories, contains beneficial amounts of iron (especially important for women of child-bearing age) and has no saturated fat or cholesterol. 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). Tofu also contains soy isoflavones, which can mimic natural human estrogens and may have a variety of harmful or beneficial effects when eaten in sufficient quantities.

Etymology

The English word "tofu" comes from the Japanese tōfu (豆腐), which derives from the Chinese dòufǔ (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).[1]

History

Tofu originated in ancient China.[2] There are many theories regarding the origins of tofu, but little historical information to prove or disprove them. It is known that tofu was widely consumed in ancient China, and that techniques for its production and preparation eventually spread to many other parts of Asia.

Three theories of origin

The most common theory about the origin of tofu origin maintains that it was invented in northern China around 164 B.C.E. by Lord Liu An, a Han Dynasty prince. Chinese folklore often attributes important inventions to well-known historical figures;[3][4] techniques of tofu production probably existed long before this time.

Another theory is that the method for producing tofu was discovered accidentally when a slurry of boiled, ground soybeans was mixed with impure sea salt, containing calcium and magnesium salts, which caused the soy mixture to curdle and produce a tofu-like gel.[5] Soy milk has been eaten as a savory soup since ancient times.[3]

A third theory 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. 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 in the etymological similarity between the Chinese term for Mongolian fermented milk (rufu, which literally means "milk spoiled") and the term doufu or tofu.[3]

In Asia

Tofu is known to have been a commonly consumed food in China by the second century B.C.E. 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 Dynasties show that the technique for the production of tofu had already been standardized by that time.

In China, tofu is traditionally presented as a food offering when visiting the graves of deceased relatives. According to tradition, tofu is the only food soft enough for the spirits (or ghosts), who have long ago lost their chins and jaws, to eat. Before refrigeration was available in China, tofu was often sold only during the winter time. During the warmer months, leftover tofu would be spoiled if not consumed within a day.

Tofu and its production technique were introduced into Japan in the Nara period (late eighth century) as well as to other parts of East Asia. The earliest documented record of tofu in Japan shows that the dish was served as an offering at the Kasuga Shrine in Nara in 1183.[6] The rise in acceptance of tofu may have coincided with the rise of Buddhism, as tofu is an important source of protein in a vegetarian diet.[4] The book Tofu Hyakuchin (豆腐百珍), published during the Edo period, lists 100 recipes for cooking tofu.

Tofu has become a staple in many countries, including Vietnam, Thailand, and Korea, with subtle regional variations in methods of production, texture, flavor, and usage.

Production

The production of tofu from soy milk is similar to the production of cheese from milk. Tofu is made by coagulating soy milk and pressing the resulting curds. Although commercial soy milk may be used, most tofu producers begin by making their own soy milk, produced by soaking, grinding, boiling, and straining dried (or, less commonly, fresh) soybeans. Some non-soy products, such as almonds or black beans, are also processed to make tofu.

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 for commercial production.[7] A third type of coagulant, enzymes, is not yet used commercially but shows potential for producing both firm and "silken" tofu.

Salt coagulants

  • Calcium sulfate (gypsum): The traditional and most widely used coagulant to produce Chinese-style tofu is calcium sulfate, which produces a tofu that is tender but slightly brittle in texture. The coagulant itself has no perceptible taste. Use of this coagulant also makes a tofu that is rich in calcium, an important mineral for treating and preventing osteoporosis. Many tofu manufacturers use calcium sulfate so that they can market their tofu as a good source of calcium.
  • Chloride-type Nigari salts or Lushui (卤水 in Chinese) - Magnesium chloride and calcium chloride: Both of these salts have a high solubility rate in water and affect soy protein in the same way; gypsum is only very slightly soluble in water and acts differently in soy protein precipitation. These coagulants produce tofu with a smooth and tender texture. In Japan, a white powder called nigari (lushui, 卤水, in China), which consists primarily of magnesium chloride, is produced from seawater after the sodium chloride is removed and the water evaporated. Depending on how it is produced, nigari/lushui 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. Calcium chloride is commonly used as a coagulant for tofu in North America.[8]

Acid coagulants

  • Glucono delta-lactone (GDL): A naturally occurring organic acid also used in cheese making, GDL produces a very fine-textured tofu that is almost jelly-like. This coagulant is used especially for "silken" and softer tofus, and gives the finished product an almost imperceptible sour taste.[9] GDL is commonly used together with calcium sulfate, to give soft tofu a smooth tender texture.

Enzyme coagulants

  • Among enzymes that have been shown to produce tofu are papain, and alkaline and neutral proteases from microorganisms. In the case of papain, the enzyme to substrate ratio, by weight, was held constant at 1:400. An aliquot of 1 percent crude papain was added to "uncooked" soy milk at room temperature and heated to 90–100 degrees Celsius.[8]

Contemporary tofu manufacturers may use a combination of these coagulants to produce a desired texture in the finished tofu.[9] Different textures result from a difference in pore sizes and other microscopic features in the tofus produced using each coagulant. The coagulant mixture is dissolved in water, and the solution is then stirred into boiled soy milk until the mixture curdles into a soft gel.[7]

The curds are processed differently, depending on the form of tofu that is being manufactured. For soft silken tofu (嫩豆腐; nèn dòufǔ) or tofu flower (豆花, dòuhuā), the soy milk is curdled directly in the container in which the tofu will be sold. For standard firm Asian tofu, the soy curd is cut and excess liquid is strained off using cheese cloth or muslin, then the curds are lightly pressed into a soft cake. Firmer tofus, such as Asian dry tofu (荳乾) or Western types of tofu, are pressed to remove even more liquid. In Vietnam, the curd is strained and molded in a square mold, and the end product is called đậu khuôn (molded bean) or đậu phụ (one of the Vietnamese ways to pronounce the Chinese “doufu”). The tofu curds are allowed to cool and become firm. The finished tofu can then be cut into pieces, flavored or further processed.

Although tartness is sometimes desired in dessert tofu, the acid used for flavoring is typically not the primary coagulant, since a concentration of acid high enough to induce coagulation would produce an unpleasant flavor and texture. A sour taste in tofu and a slight cloudiness in the liquid around are an indication of bacterial growth and spoilage.

Varieties

Many varieties of tofu are available in both Western and Eastern markets. Tofu products can be categorized either as fresh tofu, which is produced directly from soy milk, or as processed tofu, which is produced from fresh tofu. Tofu production also creates important side products which are used in various cuisines. A byproduct of the process is soy pulp (also called okara in Japanese).

Fresh tofu

There are three main varieties of fresh tofu, depending on the amount of water that is extracted from the tofu curds:

Silken tofu with soy sauce and a decorative carrot slice
  • Soft/silken tofu (嫩豆腐 or 滑豆腐, nèn dòufǔ or huá dòufǔ, in Chinese, lit. "soft tofu" or "smooth tofu"; 絹漉し豆腐, kinugoshi tōfu in Japanese, lit. "silk-filtered tofu"; 순두부, 純豆腐, sundubu in Korean, lit. "pure tofu"): This undrained tofu contains the highest moisture content of all fresh tofus.[10] Its texture can be described as similar to that of very fine custard. In Japan and Korea, traditional soft tofu is made with seawater.[11][12] Douhua (豆花, dòu huā or 豆腐花, dòufǔ huā in Chinese), or tofu brain (豆腐腦 or 豆腐脑, dòufǔ 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. Edamame tofu is a Japanese variety of kinugoshi tōfu made from edamame (fresh green soybeans); it is pale green in color and often studded with whole edamame.
  • Asian firm tofu (simply called 豆腐 lǎo dòufǔ in Chinese; 木綿豆腐, momendōfu in Japanese, lit. "cotton tofu"): Although drained and pressed, this form of fresh tofu still contains a considerable amount of moisture. It has the firmness of raw meat, but bounces back readily when pressed. The texture is similar to a firm custard. The skin retains the pattern of the muslin used to drain it. Firm tofu can be picked up easily with chopsticks.[13]
  • Western firm/dried tofu (豆乾, dòu gān in Chinese, lit. "dry tofu"): An extra firm variety with the least amount of moisture, it has the firmness of fully cooked meat, and a somewhat rubbery feel. The skin of retains the pattern of the muslin used to drain and press it. When milled and re-formed after pressin it sometimes lacks the skin with its cloth patterning. One variety pressed flat and sliced into long strings smaller than 2 mm × 2 mm, called shredded dried tofu (豆乾絲, dòu gān sī in Chinese, or simply 乾絲, gān sī), looks like loose cooked noodles, and can be served cold, stir-fried, or similar in style to Japanese aburaage.[14]

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

Processed

Many forms of processed tofus exist. Some of these processing techniques probably originated 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 flavors.

Fermented

  • Pickled tofu (豆腐乳 in Chinese, pinyin: dòufǔ 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.[15] 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 dòufǔ rǔ), red yeast rice (cultivated with Monascus purpureus) is added for color.[16]
  • Stinky tofu (臭豆腐 in Chinese, Pinyin: chòu dòufǔ): 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, but the flavor and texture of stinky tofu is appreciated by aficionados, who describe it as delightful. 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.

Flavored

Flavors can be mixed directly into the curdling soy milk while tofu is being produced.

  • Sweet: Common sweet dessert tofus include peanut tofu (落花生豆腐, luòhuāshēng dòufǔ in Chinese and jimami-dōfu in Japanese), almond tofu (杏仁豆腐, xìngrén dòufǔ 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 flavorants 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 (Japanese: 玉子豆腐, 卵豆腐, tamagodōfu) (Chinese: 蛋豆腐, dàn dòufǔ; often called 日本豆腐, rìbĕn dòufǔ, lit. "Japan bean curd") is the main type of savory flavored 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 color that can be attributed to the addition of egg and, occasionally, food coloring. This tofu has a fuller texture and flavor 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 with lower moisture content, such as firm Asian and dry tofus, are cut into bite-sized cubes or triangles and deep fried until they develop a golden-brown, crispy surface (炸豆腐 in Chinese, zhà dòufǔ, 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, and are included as part of the vegetarian dish called "Buddha's delight" (luohan zhai).

Frozen

Thawed and sliced frozen tofu
  • Thousand layer tofu (千葉豆腐, 凍豆腐 or 冰豆腐 in Chinese, lit. "thousand layer tofu" or "frozen tofu"): When tofu is frozen, the large ice crystals that develop within it form large cavities that appear to be layered (pseudostratified). The frozen tofu takes on a yellowish hue during the freezing process. “Thousand-layer tofu” is commonly made at home by freezing Asian soft tofu, though it is also commercially sold as a regional specialty in parts of Taiwan. This tofu is defrosted and sometimes squeezed of moisture prior to use.[4]
  • Koyadofu (kōyadōfu, 高野豆腐 in Japanese): The name comes from Mount Koya, a center of Japanese Buddhism famed for its shōjin ryōri, or traditional Buddhist vegetarian cuisine. It is sold in freeze-dried blocks or cubes in Japanese markets. It must be soaked in water before eating, and is typically simmered in dashi, sake or mirin and soy sauce. In shōjin ryōri, vegetarian kombu dashi, made from seaweed, is used. When prepared in the usual manner, it has a spongy texture and mild sweet, savory flavor. A similar form is found in instant soups (such as miso soup), in which the toppings are freeze-dried and stored in sealed pouches.

By-products 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 solids left over from pressing soy milk are called okara.

Tofu skin

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 soy milk skin (腐皮, fǔ pí in Chinese; 湯葉, yuba in Japanese). Its approximate composition is: 50–55 percent protein, 24–26 percent lipids (fat), 12 percent carbohydrate, 3 percent ash, and 9 percent moisture.

The skin can also be bunched up in stick form and dried into something known as "tofu bamboo" (腐竹, fǔ zhú in Chinese; phù chúc in Vietnamese; kusatake, Japanese). Tofu skin, with its soft yet rubbery texture, is folded or shaped into different forms and cooked further to imitate meat in vegetarian cuisine.

Okara

Okara (雪花菜, xuě huā caì, lit. "snowflake vegetable"; 豆腐渣, dòufǔ zhā, lit. "tofu sediment/residue"; kongbiji, 콩비지 in Korean), sometimes known in the west as soy pulp, is the fiber, 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.

Tofu made from other legumes and grains

  • Black bean tofu (黑豆花): A type of tofu made from plain black beans and soybeans, which is usually made into dòuhuā () rather than firm or dry tofu. The texture of black bean tofu is slightly more gelatinous than regular tofu flower, and the color is grayish. This type of tofu is eaten for the earthy "black bean taste."
  • Burmese tofu (to hpu in Burmese): A type of tofu made from gram (besan) or chickpea (chana dal) flour instead of soybeans; the Shan variety uses yellow split pea flour instead. Both types are yellow in color and generally found only in Myanmar, though the Burman variety is also available in some overseas restaurants serving Burmese cuisine.[17]
To hpu may be fried as fritters cut in rectangular or triangular shapes; the latter fried twice, hence the name hnapyan gyaw (literally "twice fried"), is the common form in the Shan States. To hpu nway, creamy and soft before it sets, is also popular served hot on its own or with rice noodles. To hpu gyauk, which are deep fried, thin, and crispy, are similar to prawn or fish crackers.
Rice tofu, called hsan to hpu (or hsan ta hpo in Shan regions) is made from rice flour (called hsan hmont or mont hmont) and is white in color, with the same consistency as yellow Burmese tofu when set. It is eaten as a salad in the same manner as yellow tofu.

Preparation

Tofu has very little flavor or smell of its own and can be prepared either in savory or sweet dishes, acting as a complement to the flavors of the other ingredients used. In Asian cuisine, tofu is served raw, stewed, stir-fried, in soup, cooked in sauce, or stuffed with fillings. The light, greenish "bean" smell of tofu is much enjoyed in East Asian cuisines and fresh tofu is often eaten plain or simply flavored.

In Japan, a common lunch in the summer months is hiyayakko (冷奴), silken or firm Asian tofu served with freshly grated ginger, scallions, katsuobushi (dried salmon) shavings and soy sauce. In many parts of China, fresh tofu is similarly eaten with soy sauce, century eggs (皮蛋), and sesame seed oil.

Dòuhuā (豆花), is a soft tofu dish. The fresh tofu is served warm and dressed with sweet syrup. Lamma Island, Hong Kong.

In Chinese cuisine, 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.[3]

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 Japanese hiyayakko, are also enjoyed.

In the Philippines, the sweet delicacy taho is made of fresh tofu with brown sugar syrup and sago.

In Vietnam, dòuhuā is pronounced đậu hủ. This variety of soft tofu is made and carried around in an earthenware jar. It is scooped into a bowl with a shallow, flat spoon, and is served with either powdered sugar and lime juice, or with a ginger-flavored syrup. It is generally eaten hot, even during summer.

Fried

A common cooking technique in many parts of East and Southeast Asia involves deep frying tofu in vegetable oil, sunflower oil, or canola oil. 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 (surimi) or cooked in soups.[3] 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 soaked in a sweet syrup and cut open to form a pocket; stuffed with sushi rice, this dish is called inarizushi (稲荷寿司) .

Soups, stews, and braised dishes

Tofu in hot water.

A well-known hot Sichuan preparation using firm Asian tofu is mápó dòufu (麻婆豆腐). Tofu and beef are braised in a sauce of chili, ginger and fermented bean paste. In the Shanghai region it is called málà dòufǔ (麻辣豆腐).

Dried tofu is usually not eaten raw, but stewed in a mixture of soy sauce and spices. Some types of dried tofu are pre-seasoned 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 stewed by tofu vendors.[3] 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 are rehydrated and enjoyed in savory soups. These products are often taken along on journeys; a small bag of 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 flavoring

Pickled tofu is commonly used in small amounts together with its soaking liquid to flavor 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.

Western methods

Firm tofu can be 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.

Before grilling, firm tofu is usually marinated overnight. Grated firm western tofu is sometimes used in conjunction with TVP (textured vegetable protein) as a meat substitute. Softer tofus are sometimes used as a dairy-free or low-calorie filler, or made into ice cream substitutes. Silken tofu may be used to replace cheese in certain dishes (such as lasagna) or incorporated into Indian-style curries.

Tofu and soy protein can be industrially processed to match the textures and flavors of cheese, pudding, eggs, or bacon. 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 a source of high-quality, non-animal protein.

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). Tofu is relatively high in protein, about 10.7 percent for firm tofu and 5.3 percent for soft "silken" tofu with about 2 percent and 1 percent fat respectively as a percentage of weight.[18]

Tofu contains soy isoflavones, which can mimic natural human estrogens and may have a variety of beneficial effects when eaten in sufficient quantities. Some health studies have claimed that regular consumption of tofu and soy milk alleviates symptoms of menopause, reduces the risk of osteoporosis, lowers bad cholesterol and helps prevent certain types of cancers.[19] Other studies contradict these claims.[20] [21]

Sales and distribution

In the East, tofu may be produced locally by relatively small vendors or distributed nationwide by large manufacturers. 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 sold by large manufacturers often comes packaged in sealed plastic cartons or tubes, and may be, at most, two weeks old. In Chinese supermarkets, tofu can be found in many different flavors and grades of consistency.

Most silken and flavored tofus are produced by large factories. In Japan, silken tofu without preservatives is made daily and must be sold within two days.

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.

Notes

  1. American Heritage Dictionary of the English language (Boston: Houghton Mifflin, 2006, ISBN 0395825172).
  2. History of Tofu. Soya. Retrieved December 16, 2015.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 William Shurtleff and Akiko Aoyagi, The Book of Tofu. Volume 1, Food for Mankind (Brookline, MA: Autumn Press, 1975, ISBN 0914398059). History of Tofu Retrieved June 27, 2008.
  4. 4.0 4.1 4.2 Genichi Morii and Haruo Isshi, Tofumichi (Tokyo: Shinchosha, 2004, ISBN 978-4104719013) (In Japanese)
  5. Korean sundubu (soft tofu) is still produced in a similar manner, using seawater as a coagulant.
  6. Donald Richie, A Taste of Japan (Kodansha, 2001, ISBN 4770017073).
  7. 7.0 7.1 Zeki Berk, "Technology of production of edible flours and protein products from soybeans." Retrieved December 16, 2015. FAO agricultural services bulletin, (Rome: Food and Agriculture Organization of the United Nations, 1992. ISBN 978-9251031186).
  8. 8.0 8.1 KeShun Liu, Soybeans: Chemistry, Technology, and Utilization (Springer, 1997, ISBN 978-0834212992).
  9. 9.0 9.1 Shun-Tang Guo and Tomotada Ono, “The Role of Composition and Content of Protein Particles in Soymilk on Tofu Curding by Glucono-δ-lactone or Calcium Sulfate,” Journal of Food Science 70 (4) (2005): 258–262. Retrieved June 27, 2008.
  10. William Shurtleff and Akiko Aoyagi, The Book of Tofu & Miso (Berkeley, CA: Ten Speed Press, 2000).
  11. New tofu production method. Food Production Daily. Retrieved June 27, 2008.
  12. Deep Seawater Business To Develop Local Economies Japan for Sustainability. Retrieved June 27, 2008.
  13. William Shurtleff and Akiko Aoyagi, Volume IV, The History of Traditional Non-Fermented Soyfoods, Chapter 36 (2008) History of Tofu. Retrieved June 28, 2008.
  14. A photo of aburaage. Retrieved June 21, 2008.
  15. Shurtleff and Aoyagi, Volume V, The History of Traditional Fermented Soyfoods, Chapter 44: History of Fermented Tofu (2008).
  16. The Hwang Ryh Shang Company of Taiwan, a major producer of pickled tofu, mislabels this ingredient as "red date" (jujube) on the English-language list of ingredients on its product labels, although the Chinese list of ingredients on the same product lists 紅糟 (literally "red lees," (red yeast rice).
  17. Burmese tofu recipe Netcooks.com. Retrieved June 21, 2008.
  18. Catharina Y. W. Ang, KeShun Liu, and Yao-Wen Huang, Asian Foods: Science & Technology (Lancaster, PA: Technomic Publishing Co., 1999).
  19. Soy Protein and Soy Isoflavones Penn State College of Agricultural Science. Retrieved June 21, 2008.
  20. Frank M. Sacks, et. al., "Soy Protein, Isoflavones, and Cardiovascular Health" AHA Science Advisory Circulation 113 (2006): 1034-1044 Retrieved December 16, 2015.
  21. Kathleen Doheny, "Soy Claim as Heart Helper in Dispute" HealthDay News, 2006.

References
ISBN links support NWE through referral fees

  • Anderson, J. W. B.M. Johnstone and M. E. Cook-Newell, Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids. New England Journal of Medicine 333 (5) (1995): 276–282.
  • Ang, Catharina Y. W., KeShun Liu and Yao-Wen Huang. Asian Foods: Science & Technology. Lancaster, PA: Technomic Publishing Co., 1999.
  • Berk, Zeki. 1992. Technology of production of edible flours and protein products from soybeans. FAO agricultural services bulletin 97. Rome: Food and Agriculture Organization of the United Nations. ISBN 978-9251031186.
  • Grundy, Scott M., and James Cleeman, Stephen R. Daniels, Karen A. Donato, Robert H. Eckel, and Barry A. Franklin, "Diagnosis and Management of the Metabolic Syndrome. An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement." Circulation 112 (2005): 2735-2752.
  • Guo, Shun-Tang, and Tomotada Ono, "The Role of Composition and Content of Protein Particles in Soymilk on Tofu Curding by Glucono-δ-lactone or Calcium Sulfate." Journal of Food Science 70 (4) (2005): 258–262. Retrieved December 14, 2015.
  • Liu, KeShun. Soybeans: Chemistry, Technology, and Utilization. Springer, 1997. ISBN 978-0834212992.
  • Morii, Gen ichi, Haruo Isshi. Tofumichi. Tokyo: Shinchosha, 2004. ISBN 978-4104719013. (In Japanese)
  • Sacks, Frank M. et al. Soy Protein, Isoflavones, and Cardiovascular Health. An American Heart Association Science Advisory for Professionals From the Nutrition Committee. Circulation 113 (7) (2006): 1034–1044.
  • Shurtleff, William, and Akiko Aoyagi. Tofu & soymilk production: a craft and technical manual, 3rd ed. Lafayette, CA: Soyfoods Center, 2000. ISBN 978-1928914044.
  • Shurtleff, William, and Akiko Aoyagi. The Book of Tofu: Food for Mankind. Bookthrift Co., 1985. ISBN 978-0914398059
  • Shurtleff, William, and Akiko Aoyagi. The Book of Tofu & Miso. Berkeley, CA: Ten Speed Press, 2001. ISBN 978-1580083584
  • Shurtleff, William, and Akiko Aoyagi. A Comprehensive History of Soy. History of Soybeans and Soyfoods Past Present and Future. Lafayette, CA: Soyinfo Center, 2008. Retrieved December 14, 2015.
  • White, L. R. et al. "Brain aging and midlife tofu consumption." Journal of the American College of Nutrition 19(2) (2000): 242–255.

External links

All links retrieved April 30, 2023.


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