View source for Sweet corn

{{Short description|Variety of corn}}
{{Infobox cultivar
| name = Sweet corn
| image = vegCorn.jpg
| image_caption = Husked sweet corn
| species = ''[[Zea mays]]'' convar. ''saccharata'' var. ''rugosa''
| origin = United States
}}
[[File:Sweet Corns.jpg|thumb|200px|Loose kernels of sweet corn]]

'''Sweet corn''' (''Zea mays'' convar. ''saccharata'' var. ''rugosa''),<ref>{{cite journal | first = A. T. | last = Erwin |date=July 1951 | title = Sweet Corn—Mutant or historic species? | journal = Economic Botany | volume = 5 | issue = 3 | page = 302 | publisher = Springer New York | doi=10.1007/bf02985153| bibcode = 1951EcBot...5..302E | s2cid = 28127396 }}</ref> also called '''sweetcorn''', '''sugar corn''' and '''pole corn''', is a variety of [[maize]] grown for human consumption with a high [[sugar]] content. Sweet corn is the result of a naturally occurring [[recessive]] [[mutation]] in the genes which control conversion of sugar to [[starch]] inside the [[endosperm]] of the corn kernel. Sweet corn is picked when still immature (the milk stage) and prepared and eaten as a [[vegetable]], unlike [[field corn]], which is harvested when the kernels are dry and mature (dent stage).<ref>{{cite web | url=https://hort.purdue.edu/newcrop/Crops/Corn.html | title=Corn }}</ref> Since the process of maturation involves converting sugar to starch, sweet corn stores poorly and must be eaten fresh, [[Canning|canned]], or frozen, before the kernels become tough and starchy.

It is one of the six major types of corn, the others being [[dent corn]], [[flint corn]], [[pod corn]], [[popcorn]], and [[flour corn]].<ref>Linda Campbell Franklin, "Corn," in Andrew F. Smith (ed.), ''The Oxford Encyclopedia of Food and Drink in America''. 2nd ed. Oxford: Oxford University Press, 2013 (pp. 551–558), p. 553.</ref>

According to the [[USDA]], 100 grams of raw yellow sweet corn contains 3.43&nbsp;g [[glucose]], 1.94&nbsp;g [[fructose]], and 0.89&nbsp;g [[sucrose]].<ref>[https://fdc.nal.usda.gov/fdc-app.html#/ FoodData Central (USDA)] {{Webarchive|url=https://web.archive.org/web/20230429033458/https://fdc.nal.usda.gov/fdc-app.html#/ |date=2023-04-29 }}. Search for "corn, sweet, yellow, raw" and click on "SR Legacy Foods".</ref>
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{{nutritionalvalue|
name=Sweet corn, yellow, raw<br/> (seeds only)|
kJ=360|
water=75.96 g|
protein=3.2 g|
fat = 1.18 g|
carbs=19.02 g|
fiber=2.7 g|
sugars=3.22 g|
potassium_mg=270|
magnesium_mg=37|
iron_mg=0.52| vitC_mg=6.8|
vitA_ug=9|
folate_ug=46| 
niacin_mg=1.700|
thiamin_mg=0.200|
tryptophan=0.023 g|
threonine=0.129 g|
isoleucine=0.129 g|
leucine=0.348 g|
lysine=0.137 g|
methionine=0.067 g|
cystine=0.026 g|
phenylalanine=0.150 g|
tyrosine=0.123 g|
valine=0.185 g|
arginine=0.131 g|
histidine=0.089 g|
alanine=0.295 g|
aspartic acid=0.244 g|
glutamic acid=0.636 g|
glycine=0.127 g|
proline=0.292 g|
serine=0.153 g|
source_usda=1|
right=1|
note=One ear of medium size (6-¾ to 7-½ inches long) maize has 90 grams of seeds}}

==History==
In 1493, Christopher Columbus returned to Europe with corn seeds, although this revelation did not succeed due to inadequate education of how to produce corn. Sweet corn occurs as a spontaneous mutation in [[field corn]] and was grown by several [[Indigenous peoples of the Americas|Native American]] tribes. The European cultivation of sweet corn occurred when the [[Iroquois]] tribes grew the first recorded sweet corn (called 'Papoon') for European settlers in 1779.<ref name="RJSch">Schultheis, Jonathan R. [https://web.archive.org/web/19970713003950/http://www.ces.ncsu.edu/depts/hort/hil/hil-13.html "Sweet Corn Production."] North Carolina Cooperative Extension Service, [[North Carolina State University]]. Revised 12/94.</ref> It soon became a popular food in the southern and central regions of the United States.

[[File:YoungSweetCorn.jpg|thumb|200px|Young sweet corn]]
[[File:MatureSweetCorn.jpg|thumb|200px|The same rows of corn 41 days later at maturity]]

[[Open pollination|Open pollinated]] [[cultivar]]s of white sweet corn started to become widely available in the United States in the 19th century.  Two of the most enduring cultivars, still available today, are 'Country Gentleman' (a [[Shoepeg corn]] with small kernels in irregular rows) and 'Stowell's Evergreen'.<ref>{{cite web | url = https://www.timesunion.com/living/article/Make-every-ear-count-546254.php | publisher = Times Union | title = Make every ear count | date = 6 August 2009 | access-date = 2021-04-03}}</ref>

Sweet corn production in the 20th century was influenced by the following key developments:
*[[Hybrid (biology)|hybridization]] allowed for more uniform maturity, improved quality and disease resistance
**In 1933 'Golden Cross Bantam' was released. It is significant for being the first successful single-cross hybrid and the first specifically developed for disease resistance ([[Stewart's wilt]] in this case).<ref>{{cite web | url = https://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/StewartWilt.aspx | title = Stewart's Wilt of Corn | access-date = 2014-07-07 | archive-url = https://web.archive.org/web/20171122102918/https://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/StewartWilt.aspx | archive-date = 2017-11-22 | url-status = dead }}</ref>
*identification of the separate gene mutations responsible for sweetness in corn and the ability to breed cultivars based on these characteristics:
**''su'' (normal sugary)
**''se'' (sugary enhanced, originally called Everlasting Heritage)
**''sh2'' (shrunken-2)<ref name="DLLarson">{{cite journal|last= Levey Larson|first= Debra|date= August 2003|title= Supersweet sweet corn: 50 years in the making|journal= Inside Illinois|volume= 23|issue= 3|url= http://www.news.uiuc.edu/II/03/0807/sweetcorn.html|access-date= 2009-09-03|publisher= University of Illinois at Urbana-Champaign|url-status= dead|archive-url= https://web.archive.org/web/20081012155831/http://www.news.uiuc.edu/II/03/0807/sweetcorn.html|archive-date= 2008-10-12}}</ref>

There are currently hundreds of cultivars, with more constantly being developed.{{Citation needed|date=January 2021}}

==Anatomy==
{{see also|Maize#Structure and physiology}}
The [[fruit]] of the sweet corn plant is the corn [[Corn kernel|''kernel'']], a type of fruit called a [[caryopsis]]. The ''ear'' is a collection of kernels on the [[Corncob|''cob'']]. Because corn is a [[monocot]], there is always an even number of rows of kernels.{{Explain|date=September 2010}} The ear is covered by tightly wrapped leaves called the ''[[husk]]''. ''Silk'' is the name for the [[pistil]]late flowers, which emerge from the husk. The husk and silk are removed by hand, before boiling but not necessarily before roasting, in a process called ''husking'' or ''shucking''.<ref>{{Cite journal |last=Meredith |first=Mamie J. |date=February 1938 |title=Cornhusking and Other Terms |url=https://www.jstor.org/stable/451363 |journal=American Speech |volume=13 |issue=1 |pages=19–24 |doi=10.2307/451363|jstor=451363 |url-access=subscription }}</ref>{{Citation needed|date=January 2021}}

==Consumption==
{{see also|List of maize dishes|Protein combining}}
In most of [[Latin America]], sweet corn is traditionally eaten with beans.  Although both corn and beans contain all 9 essential amino acids, eating a wide variety of foods in one day that includes grains and beans ensures the right balance of essential amino acids.<ref>Gardner CD, Hartle JC, Garrett RD, Offringa LC, Wasserman AS. (2019) Maximizing the intersection of human health and the health of the environment with regard to the amount and type of protein produced and consumed in the United States. Nutrition Reviews 77(4):197–215. doi:10.1093/nutrit/nuy073</ref> In [[Brazil]], sweet corn cut off from the cobs is generally eaten with [[pea]]s (where this combination, given the practicality of steamed canned grains in an urban diet, is a frequent addition to diverse meals such as salads, stews, seasoned white rice, risottos, soups, pasta, and whole sausage hot dogs).{{Citation needed|date=January 2021}}

In Malaysia, there exists a variety unique to the [[Cameron Highlands]] named "pearl corn". The kernels are glossy white, resembling pearls, and can be eaten raw off the cob, although they are often boiled in water and salt.<ref>{{Cite web|url=https://eatfresh.org/discover-foods/corn|title=Corn (bicolor)|website=eatFresh.org|url-status=live|archive-url=https://web.archive.org/web/20181207142430/http://eatfresh.org/discover-foods/corn|archive-date=7 December 2018|access-date=31 March 2020}}</ref>

In the Philippines, boiled sweet corn kernels are served hot with [[margarine]] and [[Powdered cheese|cheese powder]] as an inexpensive snack sold by street vendors.<ref>{{Cite web|url=http://www.ilovetansyong.com/2013/07/SweetCorn.html|title=Japanese Corn in the Philippines: So Corny! So Sweet! So Cheesy! - I ♥ Tansyong™}}</ref>

Similarly, sweet corn in [[Indonesia]] is traditionally ground or soaked with [[milk]], which makes available the [[B vitamins|B vitamin]] [[Niacin (nutrient)|niacin]] in the corn, the absence of which would otherwise lead to [[pellagra]]. Cheese and condensed milk are added to sweet corn in the snack ''[[jasuke]]'', short for ''jagung susu keju''.

In Brazil, a combination of ground sweet corn and milk is also the basis of various well-known dishes, such as ''[[pamonha]]'' and the pudding-like dessert {{lang|pt|curau}}, while sweet corn eaten directly off the cob tends to be served with butter.{{Citation needed|date=January 2021}}

In Europe and Asia sweet corn is often used as a [[pizza]] topping or in [[salads]]. [[Corn on the cob]] is a sweet corn cob that has been boiled, steamed, or grilled whole; the kernels are then cut off and eaten or eaten directly off the cob. [[Creamed corn]] is sweet corn served in a milk or cream sauce. Sweet corn can also be eaten as [[baby corn]]. [[Corn soup]] can be made adding water, butter and flour, with salt and pepper for seasoning.

In the United States, sweet corn is eaten as a steamed vegetable or on the cob, and is usually served with butter and salt. It can be found in Tex-Mex cooking in chili, tacos, and salads. Corn mixed and cooked with [[lima beans]] is one form of [[succotash]]. Sweet corn is one of the most popular vegetables in the United States, being most popular in the southern and central regions of the country, and can be purchased either fresh, canned, or frozen. Sweet corn ranks among the top ten vegetables in value and per capita consumption.

If left to dry on the plant, kernels may be taken off the cob and cooked in oil where, unlike [[popcorn]], they expand to about double the original kernel size and are often called [[corn nut]]s.{{citation needed|date=March 2023}}

=== Health benefits ===
[[File:Sweet corn.jpg|thumb|200px|Overripe sweet corn]]
Cooking sweet corn increases levels of [[ferulic acid]], which has anti-[[cancer]] properties.<ref>{{cite web| url = https://news.cornell.edu/stories/2002/08/cooking-sweet-corn-boosts-disease-fighting-nutrients | title = Cooking sweet corn boosts its ability to fight cancer and heart disease by freeing healthful compounds, Cornell scientists find | publisher = Cornell Chronicle |publication-date=2002-08-08 |access-date = 2022-01-17}}</ref>

==Cultivars==
{{Main|List of sweetcorn varieties}}
Open pollinated (non-[[Hybrid (biology)|hybrid]]) corn has largely been replaced in the commercial market by sweeter, earlier hybrids, which also have the advantage of maintaining their sweet flavor longer. ''su'' cultivars are best when cooked within 30 minutes of harvest. Despite their short storage life, many open-pollinated cultivars such as 'Golden Bantam' remain popular for home gardeners and specialty markets or are marketed as [[heirloom seed]]s. Although less sweet, they are often described as more tender and flavorful than hybrids.{{Citation needed|date=January 2021}}

===Genetics===
{{hatnote|In the following text, lowercase gene names indicate the recessive, loss-of-function mutants. The UniProt links provided are for the regular wild-type genes.}}
[[File:Sweet White Corn.jpg|thumb|200px|Cut white sweet corn. [[Shoepeg corn|"Shoepeg"]] is a popular cultivar from the 1900s.]]

Early cultivars, including those used by Native Americans, were the result of the mutant ''su'' ("sugary") or ''su1'' ({{UniProt|O22637}}) [[allele]] of an [[isoamylase]].<ref name="RJSch"/> They contain about 5–10% sugar by weight.{{Citation needed|date=January 2021}} These varieties are juicy due to the [[phytoglycogen]] content, but they lose sugar quickly after harvest, with the content halving in 24 hours.<ref name=ARWT>{{cite web |last1=Ragusea |first1=Adam |last2=Tracy |first2=William |title=How science saves sweet corn |url=https://www.youtube.com/watch?v=IIVG54wNPd0 |website=YouTube |access-date=30 January 2022 |language=en |date=August 24, 2021}}</ref>

''Supersweet corn'' are cultivars of sweet corn which produce higher than normal levels of sugar developed by [[University of Illinois at Urbana–Champaign]] professor John Laughnan.<ref name="DLLarson"/> He was investigating two specific [[gene]]s in sweet corn, one of which, the ''sh2'' mutation ({{UniProt|P55241}}, a [[Glucose-1-phosphate adenylyltransferase]]), caused the corn to shrivel when dry.  After further investigation, Laughnan discovered that the endosperm of ''sh2'' sweet corn kernels store less starch and from 4 to 10 times more sugar than normal ''su'' sweet corn.  He published his findings in 1953, disclosing the advantages of growing supersweet sweet corn, but many corn breeders lacked enthusiasm for the new supersweet corn due to the seed shiveling reducing germination rate.<ref name=ARWT/>

Illinois Foundation Seeds Inc. was the first seed company to release a supersweet corn and it was called 'Illini Xtra Sweet', but widespread use of supersweet hybrids did not occur until the early 1980s. The popularity of supersweet corn rose due to its long shelf life and large sugar content when compared to conventional sweet corn.<ref name=ARWT/>  This has allowed the long-distance shipping of sweet corn and has enabled manufacturers to can sweet corn without adding extra sugar or salt.{{Citation needed|date=January 2021}} Breeding has resolved the germination rate issue, but it is still generally true that ''sh2'' corn is less juicy than their ''su'' counterparts. ''sh2-i'' ("shrunken2-intermediate") cultivars under development exploits a different mutation on the same gene to try and create varieties that are both juicy and sweet.<ref name=ARWT/>

The third gene mutation to be discovered is the ''se'' (or ''se1'') for "sugary enhanced" allele, responsible for so-called "Everlasting Heritage" cultivars, such as 'Kandy Korn'.  Cultivars with the ''se'' alleles have a longer storage life and contain 12–20% sugar.{{Citation needed|date=January 2021}} The gene for ''Se1'' has been located.<ref>{{cite journal |last1=Zhang |first1=Xia |last2=Mogel |first2=Karl J. Haro von |last3=Lor |first3=Vai S. |last4=Hirsch |first4=Candice N. |last5=De Vries |first5=Brian |last6=Kaeppler |first6=Heidi F. |last7=Tracy |first7=William F. |last8=Kaeppler |first8=Shawn M. |title=Maize sugary enhancer1 ( se1 ) is a gene affecting endosperm starch metabolism |journal=Proceedings of the National Academy of Sciences |date=8 October 2019 |volume=116 |issue=41 |pages=20776–20785 |doi=10.1073/pnas.1902747116|pmid=31548423 |pmc=6789923 |bibcode=2019PNAS..11620776Z |doi-access=free }}</ref>
[[File:Sweet Corn.JPG|200px|thumb|Cooking turns yellow sweet corn golden]]

All of the alleles responsible for sweet corn are [[recessive]], so it must be isolated from other corn, such as field corn and [[popcorn]], that release pollen at the same time; the [[endosperm]] develops from genes from both parents, and [[heterozygous]] kernels will be tough and starchy. The ''se'' and ''su'' alleles do not need to be isolated from each other. However supersweet cultivars containing the ''sh2'' allele must be grown in isolation from other cultivars to avoid cross-[[pollination]] and resulting starchiness, either in space (various sources quote minimum quarantine distances from 100 to 400 feet or 30 to 120 m) or in time (i.e., the supersweet corn does not pollinate at the same time as other corn in nearby fields).{{Citation needed|date=January 2021}}

Modern breeding methods have also introduced cultivars incorporating multiple gene types:
*''sy'' (for ''synergistic'') adds the ''sh2'' gene to some kernels (usually 25%) on the same cob as a ''se'' base (either homozygous or heterozygous)
*''augmented sh2'' adds the ''se'' and ''su'' gene to a ''sh2'' parent
Often seed producers of the ''sy'' and ''augmented sh2'' types will use brand names or trademarks to distinguish these cultivars instead of mentioning the genetics behind them.  Generally these brands or trademarks will offer a choice of white, bi-color and yellow cultivars which otherwise have very similar characteristics.{{Citation needed|date=January 2021}}

===Genetically modified corn===
[[Genetically modified maize|Genetically modified sweet corn]] is available to commercial growers to resist certain insects or herbicides, or both.  Such transgenic varieties are not available to home or small acreage growers due to protocols that must be followed in their production.<ref name="ncga">{{cite web|title= Insect Resistance Management Fact Sheet For Bt Corn|url= http://www.ncga.com/managing-bt-technology|access-date= 2015-06-03|publisher= National Corn Growers Association|archive-date= 2015-05-09|archive-url= https://web.archive.org/web/20150509045144/http://www.ncga.com/managing-bt-technology|url-status= dead}}</ref>

== See also ==
* [[Frozen vegetables]]

==References==
{{Reflist}}
{{Commons category|position=left|Maize|<br />Maize}}

{{corn|state=collapsed}}

{{Authority control}}

[[Category:Maize varieties]]
[[Category:Vegetables]]
[[Category:Crops originating from indigenous Americans]]
[[Category:Crops originating from North America]]
[[Category:Crops originating from the United States]]
[[Category:Grasses of Mexico]]
[[Category:Grasses of North America]]
[[Category:Grasses of the United States]]
[[Category:Agriculture in Mesoamerica]]
[[Category:Cuisine of the Northeastern United States]]
[[Category:Symbols of Illinois]]