View source for Nixtamalization

{{More footnotes|date=August 2010}}
{{Use American English|date = April 2019}}
{{Short description|Procedure for preparing corn to eat}}
{{Use mdy dates|date = April 2019}}

[[File:Tortilleras Nebel.jpg|right|thumb|250px|An 1836 [[lithograph]] of [[tortilla]] production in rural Mexico]]
[[File:Hominy (maize).JPG#file|thumb|right|200px|Bowl of hominy (nixtamalized corn kernels)]]

'''Nixtamalization''' ({{IPAc-en|ˌ|n|ɪ|ʃ|t|ə|m|ə|l|ɪ|ˈ|z|eɪ|ʃ|ən|,_|ˌ|n|ɪ|k|s|-|}} {{respell|nish|tə|mə|lih|ZAY|shən}}) is a process for the preparation of [[maize]] (corn), or other [[cereal grain|grain]], in which the grain is soaked and [[cooking|cooked]] in an [[alkaline]] solution, usually [[limewater]] (but sometimes aqueous [[alkali metal]] [[carbonate]]s),<ref name=ml>{{cite web |last=Thigpen |first=Susan |title=Hominy – Mountain Recipe |url=http://www.mtnlaurel.com/recipes/160-hominy-mountain-recipe.html |work=The Mountain Laurel |access-date=17 November 2013 |date=October 1983}}</ref> washed, and then [[hulling|hulled]]. The term can also refer to the removal via an alkali process of the [[pericarp]] from other grains such as [[sorghum]].

Nixtamalized corn has several benefits over unprocessed grain: It is more easily ground, its [[nutrition]]al value is increased, [[Flavor (taste)|flavor]] and [[aroma]] are improved, and [[mycotoxin]]s are reduced by up to 97–100% (for [[aflatoxin|aflatoxins]]).<ref>{{cite book |title=Mycotoxins in Food, Feed and Bioweapons |pages=39–49 |editor1=M. Rai |editor2=A. Varma |publisher=Springer-Verlag |location=Berlin Heidelberg |year=2010 |chapter-url=http://libcatalog.cimmyt.org/download/reprints/98545.pdf |chapter=The Destruction of Aflatoxins in Corn by "Nixtamalización" |author=Doralinda Guzmán-de-Peña |access-date=2019-04-12 |doi=10.1007/978-3-642-00725-5_3|isbn=978-3-642-00724-8 }}</ref> 

Lime and ash are highly alkaline: the alkalinity helps the dissolution of [[hemicellulose]], the major glue-like component of the maize cell walls, and loosens the hulls from the kernels and softens the maize.<ref name="researchgate" /> The [[tryptophan]] in corn proteins is made more available for human absorption, thus helping to prevent [[niacin]] deficiency ([[pellagra]]).<ref name="fao92" />{{rp|at=§5.2}} Tryptophan is the metabolic precursor of endogenous niacin (Vitamin B<sub>3</sub>).

Some of the corn oil is broken down into emulsifying agents (monoglycerides and diglycerides), while bonding of the maize proteins to each other is also facilitated. The divalent calcium in lime acts as a cross-linking agent for protein and polysaccharide acidic side chains.<ref>{{cite book |title= On Food and Cooking: The Science and Lore of the Kitchen |author= Harold McGee |publisher= [[Charles Scribner's Sons|Scribner]] |location= New York, New York (USA) |url= https://books.google.com/books?id=bKVCtH4AjwgC&q=nixtamalization |date= 2004 |page= 478 |isbn= 978-0-684-80001-1 |access-date= 23 January 2013}}</ref>

While [[cornmeal]] made from untreated ground maize is unable by itself to form a dough on addition of water, nixtamalized cornmeal will form a dough, called [[masa]]. These benefits make nixtamalization a crucial preliminary step for further processing of maize into food products, and the process is employed using both traditional and industrial methods in the production of [[tortilla]]s and [[tortilla chip]]s (but not [[corn chip]]s), [[tamale]]s, [[hominy]], and many other items.

==Etymology==
In the [[Aztec]] language [[Nahuatl]], the word for the product of this procedure is {{lang|nah|nixtamalli}} or {{lang|nah|nextamalli}} ({{IPA|nah|niʃtaˈmalːi|pron}} or {{IPA|nah|neʃtaˈmalːi|}}), which in turn has yielded [[Mexican Spanish]] {{lang|es-MX|nixtamal}} ({{IPA|es|nistaˈmal|}}). The Nahuatl word is a compound of {{lang|nah|nextli}} "[[calcium hydroxide|lime]] ashes" and {{lang|nah|tamalli}} "unformed/cooked corn dough, [[tamale|tamal]]".<ref>{{cite book|last1=Días Roig|first1=Mercedes|last2=Miaja|first2=María Teresa|publisher=El Colegio de México|title=Naranja dulce, limón partido|edition=1st|language=es|year=1979|location=México City|isbn=968-12-0049-7|page=137}}</ref> The term ''nixtamalization'' can also be used to describe the removal of the pericarp from any grain by an alkali process, including maize, [[sorghum]], and others. When the unaltered Spanish spelling {{lang|es-MX|nixtamalización}} is used in written English, however, it almost exclusively refers to maize.

The labels on packages of commercially sold tortillas prepared with nixtamalized maize usually list ''corn treated with lime'' as an ingredient in English, while the Spanish versions list {{lang|es-MX|maíz nixtamalizado}}.

==History==
===Mesoamerica===
[[File:Dried Maize Mote from Oaxaca.png|thumb|right|Dried, treated maize sold in [[Oaxaca]], Mexico ([[quarter (United States coin)|US quarter]] and [[Mexican peso]] shown for scale)]]
The process of nixtamalization was first developed in [[Mesoamerica]], where [[maize]] was originally cultivated. There is no precise date when the technology was developed, but the earliest evidence of nixtamalization is found in Guatemala's southern coast, with equipment dating from 1200 to 1500 BC.<ref name="staller">{{cite book|last1=Staller|first1=John E.|last2=Carrasco|first2=Michael|title=Pre-Columbian Foodways: Interdisciplinary Approaches to Food, Culture, and Markets in Ancient Mesoamerica|year=2009|publisher=Springer-Verlag|location=Berlin|page=317|isbn=978-1-4419-0471-3}}</ref>

How nixtamalization was discovered is not known, but one possibility may have been through the use of hot stones (see [[pot boiler]]) to boil corn in early cultures which did not have cooking vessels robust enough to put directly on fire or coals. In limestone regions like those in Guatemala and southern Mexico, heated chunks of limestone would naturally be used, and experiments show that hot limestone makes the cooking water sufficiently alkaline to cause nixtamalization. Archaeological evidence supporting this possibility has been found in southern Utah, United States.<ref>{{cite journal |title=Stone-boiling maize with limestone: experimental results and implications for nutrition among SE Utah preceramic groups |journal=Journal of Archaeological Science |volume=40 |pages=35–44 |doi=10.1016/j.jas.2012.05.044 |year=2013 |last1=Ellwood |first1=Emily C. |last2=Scott |first2=M. Paul |last3=Lipe |first3=William D. |last4=Matson |first4=R.G. |last5=Jones |first5=John G. |issue=1 |bibcode=2013JArSc..40...35E |url=https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1172&context=agron_pubs }}</ref>

The [[Aztec]] and [[Maya civilization|Maya]] civilizations developed nixtamalization using slaked lime ([[calcium hydroxide]]) and lye ([[potassium hydroxide]]) to create alkaline solutions. The [[Chibcha]] people to the north of the ancient [[Inca]] also used calcium hydroxide (also known as "cal"), while the tribes of North America used [[soda ash]].

The nixtamalization process was very important in the early Mesoamerican diet, as there is very little [[Vitamin B3|niacin]] in corn and the tryptophan within is unavailable without processing.<ref name=fao92/>{{rp|at=§5.2}} A population that depends on untreated maize as a [[staple food]] risks malnourishment and is more likely to develop [[deficiency disease]]s such as [[pellagra]], niacin deficiency, or [[kwashiorkor]], the absence of certain amino acids that maize is deficient in. Maize cooked with lime or other alkali provided bioavailable niacin to Mesoamericans. Beans provided the otherwise missing amino acids required to balance maize for [[complete protein]].<ref name=fao92/>{{rp|at=§8}}

=== Spread ===
The spread of maize cultivation in the Americas was accompanied by the adoption of the nixtamalization process. Traditional and contemporary regional cuisines (including [[Maya cuisine]], [[Aztec cuisine]], and [[Mexican cuisine]]) included, and still include, foods based on nixtamalized maize.

The process has not substantially declined in usage in the [[Mesoamerican region]], though there has been a decline in North America. Many Native North American tribes, such as the [[Wyandot people|Huron]], no longer use the process.{{Citation needed|date=February 2008}} In some Mesoamerican and North American regions, dishes are still made from nixtamalized maize prepared by traditional techniques. The [[Hopi]] produce sodium carbonate from ashes of various native plants and trees.<ref>{{cite book|access-date=2007-10-15|title=Diabetes As a Disease of Civilization: The Impact of Culture Change on Indigenous People |author1=Jennie Rose Joe |author2=Robert S. Young |url=https://books.google.com/books?id=Io0sdbsTK08C |year=1993 |publisher=Walter de Gruyter |isbn=978-3-11-013474-2}}</ref><ref>{{cite book|url=https://books.google.com/books?id=B_y0ekzJvwQC|title=American Indian Food|author=Linda Murray Berzok|year=2005|publisher=Greenwood Press|access-date=2007-10-15 |isbn=978-0-313-32989-0}}</ref> Some contemporary Maya use calcium salts in the form of ashes of burnt mussel shells or heated limestone.<ref>{{cite web |title=Guatemalan Tortillas: How To Make Them And Why To Eat Them |url=https://www.healthacrosscultures.com/guatemalan-tortillas/ |access-date=2018-08-03 }}</ref>

By AD 900, nixtamalizing maize based foodways began to spread to the American Southeast, serving as the dietary basis for what would come to be called [[Mississippian culture]] populations. The most important nixtamalzing dish was hominy, a dish of boiled maize kernels, either ground or whole, that were nixtamalized using woodash or wood ash lye, both made from the ashes of hardwood trees.<ref>{{Cite journal |last=Briggs |first=Rachel |date=2015 |title=The Hominy Foodway of the Historic Native Eastern Woodlands |url=https://muse.jhu.edu/article/583900/pdf?casa_token=ALx0F-rsLiUAAAAA:LZkycF6lcAEkzfA77TOselum16rI4zKX1V5-Md8L_aRvj9r0aEdcduoCcQyaO2G2f9DGvSmvkaey |journal=Native South }}</ref> The continuation of the hominy foodway after European colonization helped reduce cases of pellagra within twentieth century Native populations.<ref>{{cite book |last=Briggs |first=Rachel V. |title=Detangling Histories of Hominy |url=https://www.researchgate.net/publication/328542509_Detangling_Histories_of_Hominy_A_Historical_Anthropological_Approach |year=2018 |publisher=University of Alabama Press}}</ref>

In the United States, European settlers rarely adopted the nixtamalization process, considering it unnecessary and not to their taste, though maize became a staple among the poor of the southern states.<ref>{{cite book |last=Briggs |first=Rachel V. |title=Detangling Histories of Hominy |url=https://www.researchgate.net/publication/328542509_Detangling_Histories_of_Hominy_A_Historical_Anthropological_Approach |year=2018 |publisher=University of Alabama Press}}</ref> This led to endemic [[pellagra]] in poor populations throughout the southern US in the early 20th century.<ref>{{cite book |last=Latham |first=Michael C. |title=Human Nutrition in the Developing World |url=https://archive.org/details/bub_gb_diGLEXZEGh8C |year=1997 |publisher=Food & Agriculture Org. |isbn=9789251038185 |page=[https://archive.org/details/bub_gb_diGLEXZEGh8C/page/n189 183]}}</ref> A more varied diet and fortification of wheat flour, the other staple food, have essentially eliminated this deficiency.<ref>{{cite book |last1=Rucker |first1=Robert B. |last2=Zempleni |first2=Janos |last3=Suttie |first3=John W. |author4=Donald B. McCormick |author4-link=Donald B. McCormick |title=Handbook of Vitamins, Fourth Edition |url=https://books.google.com/books?id=6fYso23Mi5IC&pg=PA192 |year=2010 |publisher=CRC Press |isbn=978-1-4200-0580-6 |page=192}}</ref>

Although maize cultivation spread far beyond the Americas via [[colonialism]], the process of nixtamalization did not. For this reason, outbreaks of pellagra occurred in many areas of Europe, where corn often became a staple crop due to its high caloric efficiency relative to the land use required for its cultivation.<ref>{{Cite journal |last=Andreescu |first=Oana |last2=Rogozea |first2=Liliana |date=2018 |title=PELLAGRA, A SOCIAL DISEASE IN AN EASTERN EUROPEAN COUNTRY, AT THE END OF THE NINETEENTH CENTURY AND EARLY TWENTIETH CENTURY |url=https://revmedchir.ro/index.php/revmedchir/article/view/1468 |journal=The Medical-Surgical Journal |via=revmedchir.ro}}</ref> A prominent example of endemic pellagra occurred in northern Italy in the late 19th century, from which the English term pellagra derives: "pel" meaning skin and "agra" meaning rough or sour in the [[Bergamo]] dialect.<ref>{{Cite journal |last=Ginnaio |first=Monica |date=2011 |title=Pellagra in Late Nineteenth Century Italy: Effects of a Deficiency Disease |url=http://www.cairn.info/revue-population-english-2011-3-page-583.htm |journal=Population (english edition) |language=fr |volume=66 |issue=3 |pages=583 |doi=10.3917/pope.1103.0583 |issn=1634-2941|url-access=subscription }}</ref>

==Process==
===Cooking===
[[File:Nixtamalized Corn maize El Salvador recipe.jpg|thumb|right|Dry maize, boiled in lime (right) and untreated (left). In this case, typical of El Salvador, a pound of maize (454 g) is boiled with a tablespoon of lime (15 mL) for 15 minutes, left to stand for a few hours, and washed with fresh water. The hulls are removed, and the kernels ground into ''masa''. Exact methods vary by use and region.]]

In the first step of nixtamalization, kernels of dried maize are [[Alkaline hydrolysis|cooked in an alkaline solution]] at or near the mixture's boiling point. After cooking, the maize is steeped in the cooking liquid for a period. The length of time for which the maize is boiled and soaked varies according to local traditions and the type of food being prepared, with cooking times ranging from a few minutes to an hour, and soaking times from a few minutes to about a day.

During cooking and soaking, a number of chemical changes take place in the grains of maize. Because plant cell wall components, including [[hemicellulose]] and [[pectin]], are highly soluble in alkaline solutions, the kernels soften and their pericarps (hulls) loosen. The grain hydrates and absorbs calcium or [[potassium]] (depending on the alkali used) from the cooking solution. Starches swell and [[starch gelatinization|gelatinize]], and some starches disperse into the liquid. Certain chemicals{{which|date=August 2019}} from the germ are released that allow the cooked grains to be ground more easily, yet make dough made from the grains less likely to tear and break down. Cooking changes the grain's protein matrix, which makes proteins and nutrients from the [[endosperm]] of the kernel more available to the human body.

=== Extraction ===
After cooking, the alkaline liquid (known as '''nejayote'''), containing dissolved hull, starch, and other corn matter, is decanted and discarded (or sometimes used for making [[amate]] bark paper).<ref>{{cite book |last= von Hagen |first= Victor Wolfgang |author-link= Victor Wolfgang von Hagen |title= The Aztec and Maya Papermakers |publisher= J. J. Augustin Publisher |year= 1944 |page= 57 |isbn= 978-0-87817-206-1}}</ref> The kernels are washed thoroughly of remaining nejayote, which has an unpleasant flavor. The [[pericarp]] is then removed, leaving the [[endosperm]] of the [[whole grain|grain]] with or without the [[cereal germ|germ]], depending on the process.<ref>{{cite web |title=What is Hominy? |url=http://www.buzzle.com/articles/what-is-hominy.html |archive-url=https://web.archive.org/web/20110202071113/http://www.buzzle.com/articles/what-is-hominy.html |url-status=usurped |archive-date=February 2, 2011 |access-date=2011-01-31}}</ref><ref>{{cite web |title=Nixtamalization, a Mesoamerican technology |url=http://74.6.238.252/search/srpcache?ei=UTF-8&p=nixtamalization+germ&fr=altavista&u=http://cc.bingj.com/cache.aspx?q=nixtamalization+germ&d=4892844087183950&mkt=en-US&setlang=en-US&w=f7949c99,15694ecd&icp=1&.intl=us&sig=Rl3KbkpqQ_QD4uM69aUYCg-- |access-date=2011-01-31 }}{{dead link|date=April 2018 |bot=SheriffIsInTown |fix-attempted=yes }}</ref><ref>{{cite web |title=Technological Limitations of the Nixtamalization Process |url=http://www.maiztortilla.com/en/introduction/limitations.htm |access-date=2011-01-31 |url-status=live |archive-url=https://web.archive.org/web/20110714022421/http://www.maiztortilla.com/en/introduction/limitations.htm |archive-date=2011-07-14 }}</ref><ref>{{cite web |title=Selective Nixtamalization of Fractions of Maize Grain |url=http://academic.research.microsoft.com/Paper/12460489.aspx |access-date=2011-01-31 |url-status=live |archive-url=https://web.archive.org/web/20110728100059/http://academic.research.microsoft.com/Paper/12460489.aspx |archive-date=2011-07-28 }}</ref><ref>{{cite web |title=What's the difference between corn meal and corn masa? |date=November 4, 2010 |url=http://www.joepastry.com/2010/11/04/ |access-date=2011-01-31 |url-status=live |archive-url=https://web.archive.org/web/20110713112935/http://www.joepastry.com/2010/11/04/ |archive-date=2011-07-13 }}</ref> This hulling is performed by hand, in traditional or very small-scale preparation, or mechanically, in larger scale or industrial production.

The prepared grain is called hominy or nixtamal. Nixtamal has many uses, contemporary and historic. Whole nixtamal may be used fresh or dried for later use. Whole nixtamal is used in the preparation of [[pozole]], [[menudo (soup)|menudo]], and other foods. Ground fresh nixtamal is made into ''masa'' (nixtamal [[dough]]) and used to make [[tortilla]]s, [[tamale]]s, and [[pupusa]]s. Dried and ground, it is called ''masa harina'' or instant ''masa'' flour, and is reconstituted and used like ''masa''.

The term hominy may refer to whole, coarsely ground, or finely ground nixtamal, or to a cooked porridge (also called [[samp]]) prepared from any of these.

===Enzymatic nixtamalization===
An alternative process for use in industrial settings has been developed known as '''enzymatic nixtamalization''', which uses [[protease]] enzymes to accelerate the changes that occur in traditional nixtamalization, a technique borrowed from modern [[corn wet-milling]]. In this process, corn or corn meal is first partially hydrated in hot water, so that enzymes can penetrate the grain, then soaked briefly (for approximately 30 minutes) at {{convert|50|–|60|C}} in an alkaline solution containing protease enzymes. A secondary enzymatic digestion may follow to further dissolve the pericarp. The resulting nixtamal is ground with little or no washing or hulling.

By pre-soaking the maize, minimizing the alkali used to adjust the pH of the alkaline solution, reducing the cooking temperature, accelerating processing, and reusing excess processing liquids, enzymatic nixtamalization can reduce the use of energy and water, lower nejayote (alkaline wastewater) production, decrease maize lost in processing, and shorten the production time (to approximately four hours) compared to traditional nixtamalization with only a minor loss in quality.<ref>{{cite patent |country=US |number=6428828 |status=patent |title= Enzymatic process for nixtamalization of cereal grains |gdate=2002-08-06 |fdate=2000-08-22 |inventor1-first=David S. |inventor1-last=Jackson |inventor2-first=Deepak |inventor2-last=Sahai |assign1=NuTech Ventures Inc |url=https://patents.google.com/patent/US6428828B1/en}}</ref>

==Impact on health==
The primary nutritional benefits of nixtamalization arise from the alkaline processing involved. The processing renders the protein more digestible, allowing [[tryptophan]] to be absorbed by humans. Humans can convert tryptophan into niacin, thus helping to prevent [[pellagra]]. Other measures of [[protein quality]] are also improved.<ref name=fao92>{{cite book |title=Maize in human nutrition |date=1992 |publisher=Food and Agriculture Organization of the United Nations |location=Rome |isbn=9789251030134|url=https://www.fao.org/3/T0395E/T0395E00.htm}} &ndash; Section 5.2 "Lime-treated maize (part II)", Section 8 "Improvement of maize diets"</ref>{{rp|at=§5.2}} It was originally thought that the anti-pellagra action stems from increased availability of niacin (compared to a hemicellulose-bound form called "niacytin"),<ref name="researchgate">{{Cite journal |url=https://www.researchgate.net/publication/228453826 |title=Nixtamalization, a Mesoamerican technology to process maize at small-scale with great potential for improving the nutritional quality of maize based foods |last=Wacher |first=Carmen |date=2003-01-01 |journal=Food Based Approaches for a Healthy Nutrition in Africa |url-status=live |archive-url=https://web.archive.org/web/20180305202539/https://www.researchgate.net/publication/228453826_Nixtamalization_a_Mesoamerican_technology_to_process_maize_at_small-scale_with_great_potential_for_improving_the_nutritional_quality_of_maize_based_foods |archive-date=2018-03-05}}</ref> but multiple experiments have disproven this theory.<ref name=fao92/>{{rp|at=§5.2}}

Secondary benefits can arise from the grain's absorption of minerals from the alkali used or from the vessels used in preparation. These effects can increase [[calcium]] (by 750%, with 85% available for absorption), [[iron]], [[copper]], and [[zinc]].<ref name="researchgate"/> 

Nixtamalization significantly deactivates [[mycotoxin]]s which are putative [[carcinogens]]. [[Aflotoxin]]s are reduced by 90–94%. [[Fumonisin]]s are reduced by 82%.<ref name="researchgate"/>

==References==
{{reflist}}
{{Refbegin}}
*Coe, Sophie. America's First Cuisines (1994). {{ISBN|0-292-71159-X}}
*Davidson, Alan. Oxford Companion to Food (1999), "Nixtamalization", p.&nbsp;534. {{ISBN|0-19-211579-0}}
*Kulp, Karen and Klaude J. Lorenz (editors). Handbook of Cereal Science and Technology (2000), p.&nbsp;670. {{ISBN|0-8247-8358-1}}
*McGee, Harold. On Food and Cooking, 2nd Edition (2004) p.&nbsp;477–478 {{ISBN|0-684-80001-2}}
*Smith, C. Wayne, Javier Betrán and E. C. A. Runge (editors). Corn: Origins, History and Technology (2004) p.&nbsp;275 {{ISBN|0-471-41184-1}}
{{Refend}}

{{Corn}}
{{Cooking techniques}}

[[Category:Cooking techniques]]
[[Category:Mexican cuisine]]
[[Category:Mesoamerican cuisine]]
[[Category:Maize]]
[[Category:Food processing]]

[[de:Mais#Nixtamalisation]]