Editing Longan

{{Short description|Species of tropical fruit-bearing tree}}
{{About|the fruit and tree|other uses|Long'an (disambiguation)|places in China|Longnan|and|Longyan}}
{{Distinguish|Loganberry}}

{{Use dmy dates|date=August 2021}}
{{Speciesbox
|name = Longan
|image = Longan tree at Pine Island Nursery.jpg
|image_alt = Photograph of a broadly spreading tree
|status = DD
|status_system = IUCN3.1
|status_ref =<ref name=IUCN>{{cite iucn | author = Barstow, M. | title = ''Dimocarpus longan'' | page = e.T32399A67808402 | year = 2022 | access-date = 29 January 2023}}</ref>
|genus = Dimocarpus
|species = longan
|authority = [[João de Loureiro|Lour.]]<ref name=TPL>{{ThePlantList | access-date=5 September 2016}}</ref>
|synonyms =
    {{Plainlist | style = margin-left: 1em; text-indent: -1em; |
*''Dimocarpus undulatus'' <small>Wight</small>
*''Euphoria cinerea'' <small>(Turcz.) Radlk.</small>
*''Dimocarpus leichhardtii''<small>S.T. Reynolds</small>
*''Euphoria glabra'' <small>Blume</small>
*''Euphoria gracilis'' <small>Radlk.</small>
*''Euphoria leichhardtii'' <small>Benth.</small>
*''Euphoria longan'' <small>(Lour.) Steud.</small>
*''Euphoria longana'' <small>Lam.</small>
*''Euphoria malaiensis'' <small>(Griff.) Radlk.</small>
*''Euphoria microcarpa'' <small>Radlk.</small>
*''Euphoria nephelioides'' <small>Radlk.</small>
*''Euphoria verruculosa'' <small>Salisb.</small>
*''Nephelium longan'' <small>(Lour.) Hook.</small>
*''Nephelium longana'' <small>Cambess.</small>
    }}
|synonyms_ref =<ref name=TPL/>
}}
{{Infobox Chinese
|pic=Longan (Chinese characters).svg
|piccap="Longan" in Traditional (top) and Simplified (bottom) Chinese characters
|picupright=0.45
|t=龍眼
|s=龙眼
|p=lóngyǎn
|w=lung<sup>2</sup>-yen<sup>3</sup>
|bpmf=ㄌㄨㄥˊ　ㄧㄢˇ
|mi={{IPAc-cmn|l|ong|2|.|yan|3}}
|suz=lón-ngê
|y=lùhng-ngáahn
|j=lung<sup>4</sup>-ngaan<sup>5</sup>
|ci={{IPAc-yue|l|ung|4|.|ng|aan|5}}
|poj=lêng-géng
|tl=lîng-gíng
|l='dragon eye'
}}

'''''Dimocarpus longan''''', commonly known as the '''longan''' ({{IPAc-en|ˈ|l|ɒ|ŋ|a:|n|}}) and '''dragon's eye''', is a tropical tree species that produces edible fruit.<ref name="Julia Morton">{{Cite book|title=Longan; In: Fruits of Warm Climates|last=Morton|first=Julia F.|publisher=NewCrop, Center for New Crops and Plant Products, Department of Horticulture and Landscape Architecture, Purdue University|year=1987|location=W. Lafayette, IN, USA|pages=259–262|url=https://hort.purdue.edu/newcrop/morton/longan.html}}</ref> It is one of the better-known tropical members of the soapberry family [[Sapindaceae]], to which the [[lychee]] and [[rambutan]] also belong.<ref name="Julia Morton" /> The fruit of the longan is similar to that of the lychee, but is less aromatic in taste.<ref name="Fruiting pattern">{{Cite journal|last1=Pham|first1=V.T.|last2=Herrero|first2=M.|title=Fruiting pattern in longan, Dimocarpus longan: from pollination to aril development|journal=Annals of Applied Biology|volume=169|issue=3|pages=357–368|doi=10.1111/aab.12306|year=2016|hdl=10261/135703|url=https://digital.csic.es/bitstream/10261/135703/1/HormazaI_AnnApplBiol_2016.pdf|hdl-access=free}}</ref>

The longan (from [[Vietnamese language|Vietnamese]] ''long nhãn''<ref name="Lour1790">{{cite book|last=Loureiro|first=J. de|year=1790|title=Flora Cochinchinensis|volume=I|location=Lisbon|publisher=Ulyssipone|url=https://www.biodiversitylibrary.org/item/192210#page/259/mode/1up|language=la}}</ref> or [[Cantonese]] ''lùhng ngáahn'' {{lang|zh|龍眼}}, literally 'dragon eye'), is so named because the black seed within the shelled fruit creates the appearance of an eyeball. The plant is native to tropical Asia and China.<ref>{{GRIN|access-date=11 December 2017}}</ref>

== Description ==

Depending upon climate and soil type the tree may grow to over {{Convert|100|ft|m|order=flip}}<ref>{{cite web |last1=Crane |first1=Jonathan H. |last2=Balerdi |first2=Carlos F. |last3=Sargent |first3=Steven A. |last4=Maguire |first4=Ian |date=November 1978 |title=Longan Growing in the Florida Home Landscape |url=http://edis.ifas.ufl.edu/mg049 |access-date=4 April 2017 |website=University of Florida |edition=2016}}</ref> in height, but it typically stands {{Convert|30|-|40|ft|0|abbr=on|order=flip}} in height and the [[Crown (botany)|crown]] is round.<ref name="Julia Morton" /><ref name="Crane Balerdi">{{cite web |last1=Crane |first1=Jonathan |last2=Balerdi |first2=Carlos |last3=Sarge |first3=Steven |last4=Maguire |first4=Ian |date=2015 |title=Longan Growing in the Florida Home Landscape |url=http://www.edis.ifas.ufl.edu/mg049 |access-date=5 April 2017 |website=IFAS University of Florida}}</ref> The trunk is {{Convert|80|cm|ft|abbr=on|frac=2}} thick<ref name="Julia Morton" /> with corky [[bark (botany)|bark]].<ref name="Crane Balerdi" /> The branches are long and thick, typically drooping.<ref name="Julia Morton" />

The [[leaves]] are oblong and blunt-tipped, usually {{Convert|4|-|8|in|cm|0|order=flip}} long and {{Convert|2|in|cm|0|abbr=on|order=flip}} wide.<ref name="Julia Morton" /> The leaves are [[pinnately]] compounded and alternate.<ref name="Crane Balerdi" /> There are 6 to 9 pairs of leaflets per leaf<ref name="Crane Balerdi" /> and the upper surface is wavy and a dark, glossy-green.<ref name="Julia Morton" />

The longan tree produces light-yellow [[inflorescence]]s at the end of branches.<ref name="Julia Morton" /> The inflorescence is commonly called a [[panicle]]; they can be {{Convert|4|-|18|in|cm|abbr=on|order=flip}} long, and widely branched.<ref name="Crane Balerdi" /> The small [[flower]]s have 5 to 6 [[sepal]]s and brownish-yellow [[petal]]s.<ref name="Crane Balerdi" /> The flower has a two-lobed [[pistil]] and 8 [[stamen]]. There are three flower types, distributed throughout the panicle;<ref name="Julia Morton" /> staminate (functionally male), pistillate (functionally female), and [[Hermaphrodite|hermaphroditic]] flowers.<ref name="Crane Balerdi" /> Flowering occurs as a progression.<ref name="Crane Balerdi" />

The fruit are spherical and about {{Convert|1|in|cm|1|abbr=on|order=flip}} wide; they hang in drooping clusters. The shell is tan, thin, and leathery with tiny hairs;<ref name="Crane Balerdi" /> when firm, it can be squeezed (as in the cracking of a [[sunflower seed]]) to shell the fruit.{{Citation needed|date=August 2024}} The flesh is translucent, and the [[seed]] is large and black with a circular white spot at the base.<ref name="Julia Morton" /><ref name="Crane Balerdi" /> This gives the illusion of an eye.<ref name="Julia Morton" /> The flesh has a musky, sweet taste, which can be compared to the flavor of [[lychee]] fruit.<ref name="Julia Morton" /> The seed is round, hard, and has a lacquered appearance.{{Citation needed|date=August 2024}}

The longan tree is somewhat sensitive to [[frost]]. While the species prefers temperatures that do not typically fall below {{Convert|4.5|C|F|-1}}, it can withstand brief temperature drops to about {{Convert|-2|C|F}}.<ref>{{Cite book |last=Herbst |first=S. & R. |title=The Deluxe Food Lover's Companion |publisher=Barron's Educational Series |year=2009 |via=Credo Reference}}</ref> Longan trees prefer sandy soil with mild levels of acidity and [[Soil#Soil organic matter|organic matter]].<ref name="Julia Morton" /> Longans usually bear fruit slightly later than lychees.<ref>{{Cite journal |last1=Jiang |first1=Yueming |last2=Zhang |first2=Zhaoqi |date=November 2002 |title=Postharvest biology and handling of longan fruit (Dimocarpus longan Lour.) |journal=Postharvest Biology and Technology |volume=26 |issue=3 |pages=241–252 |doi=10.1016/s0925-5214(02)00047-9}}</ref>

{{gallery|mode=packed
|Longan (Dimocarpus longan) Tree lower trunk.jpg|Lower trunk
|Longan (Dimocarpus longan) Tree leaves.jpg|Tree leaves
|Longan (Dimocarpus longan) baby fruits and leaves.jpg|Branch of baby fruits
|Dimocarpus_longan_fruits.jpg|Bunch of fruit
|Longan fruits and seed.jpg|Fruits with seed
|Longan Wiki1.webm|Longan being peeled and eaten
}}

==Taxonomy==
[[File:Longan seed.jpg|thumb|Seed]]
The longan is believed to originate from the mountain range between [[Myanmar]] and southern China. Other reported origins include Indonesia, India, [[Sri Lanka]], [[upper Myanmar]], north Thailand, [[Kampuchea]] (more commonly known as Cambodia), north [[Vietnam]] and [[New Guinea]].<ref name="TK Lim">{{Cite book |title=Edible Medicinal And Non-Medicinal Plants: Volume 6, Fruits |last=Lim |first=T.K. |chapter=Dimocarpus longan subsp. longan var. longan|publisher=Springer Science & Business Media |year=2013 |isbn=978-94-007-5628-1 |pages=18–29}}</ref>

Its earliest record of existence draws back to the [[Han dynasty]] in 200 [[BCE]]. The emperor had demanded lychee and longan trees to be planted in his palace gardens in [[Shaanxi]], but the plants failed. Four hundred years later, longan trees flourished in other parts of China like [[Fujian]] and [[Guangdong]], where longan production soon became an industry.<ref name="BPU">{{Cite book|title=Litchi and Longan: Botany, Production and Uses| last1=Menzel| first1=C.|last2=Waite |first2=G.K. |last3=Mitra |first3=S.K. |publisher=CAB International| year=2005| isbn=9781845930226|via=ProQuest ebrary}}</ref>

Later on, due to immigration and the growing demand for nostalgic foods, the longan tree was officially introduced to Australia in the mid-1800s, Thailand in the late-1800s, and Hawaii and Florida in the 1900s. The warm, sandy-soiled conditions allowed for the easy growth of longan trees. This jump-started the longan industry in these locations.<ref name="BPU" />

Despite its long success in China, the longan is considered to be a relatively new fruit to the world. It has only been acknowledged outside of China in the last 250 years.<ref name="BPU" /> The first European acknowledgment of the fruit was recorded by [[João de Loureiro]], a Portuguese Jesuit botanist, in 1790. The first entry resides in his collection of works, ''Flora Cochinchinensis''.<ref name="Lour1790" /><ref name="Fruiting pattern" />

=== Subspecies ===
[[Plants of the World Online]] lists:<ref>{{cite web |title=Dimocarpus longan Lour. &#124; Plants of the World Online &#124; Kew Science |url=http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:782795-1 |website=Plants of the World Online}}</ref>
* ''D. longan'' var. ''echinatus'' Leenhouts (Borneo, Philippines)
* ''D. longan'' var. ''longetiolatus'' Leenhouts (Viet Nam)
* ''D. longan'' subsp. ''malesianus'' Leenh. (widespread SE Asia)
* ''D. longan'' var. ''obtusus'' (Pierre) Leenh. (Indo-China)

== Conservation ==
The wild longan population have been decimated considerably by large-scale logging in the past, and the species used to be listed as [[Vulnerable species|Vulnerable]] on the [[IUCN Red List]]. If left alone, longan tree stumps will resprout and the listing was upgraded to [[Near Threatened]] in 1998. Recent field data are inadequate for a contemporary IUCN assessment.<ref name="IUCN" />

== Diseases ==
Plant based diseases can affect both longan fruits and their trees, and the severity of these diseases can range from harmless cosmetic damage to rendering to the fruit inedible.

The most prevalent disease among longan plants is [[witch's broom]], which can be found in all major longan-producing Asian territories, including China, Thailand, and Vietnam.<ref>{{Cite journal |last1=Olesen |first1=T. |last2=Menzel |first2=C. M. |last3=Wiltshire |first3=N. |last4=McConchie |first4=C. A. |date=2002 |title=Flowering and shoot elongation of lychee in eastern Australia |url=http://dx.doi.org/10.1071/ar01179 |journal=Australian Journal of Agricultural Research |volume=53 |issue=8 |pages=977 |doi=10.1071/ar01179 |issn=0004-9409}}</ref> Witch's broom deforms longan skin, and at times causes the plant to prematurely drop its fruit, similar to the ''[[Phytophthora palmivora]]''.<ref>{{Cite journal |last1=So |first1=Vera |last2=Zee |first2=S.-Y. |date=September 1972 |title=A New Virus of Longan (''Euphoria longana'' Lam.) in Hong Kong |url=http://dx.doi.org/10.1080/09670877209411804 |journal=PANS Pest Articles & News Summaries |volume=18 |issue=3 |pages=283–285 |doi=10.1080/09670877209411804 |issn=0030-7793}}</ref>

Another common disease that longan trees can carry is the aptly named ''longan decline'', which is largely prevalent in Thailand, with reports finding that it could affect up to 40% of longan trees alone.<ref name=":0">{{Cite book |url=http://dx.doi.org/10.1079/9780851996967.0000 |title=Litchi and longan: botany, production and uses |date=2005 |isbn=9780851996967 |editor-last=Menzel |editor-first=C. M. |doi=10.1079/9780851996967.0000 |editor2-last=Waite |editor2-first=G. K.}}</ref> Affected trees are more vulnerable to common tree pests and algae, and often bear low-quality fruit unworthy of yield.<ref name=":0" />

''Algal spot'' is another plant disease that can affect longan plants and trees. Common among tropical fruits, the disease mainly takes form as red-orange algae that can appear on a fruit-bearing tree's leaves or branches.<ref>{{Cite journal |last=Visarathanonth |first=N. |date=December 1990 |title=A Survey of Some Temperate Fruit Diseases in Thailand |url=http://dx.doi.org/10.17660/actahortic.1990.279.67 |journal=Acta Horticulturae |issue=279 |pages=609–618 |doi=10.17660/actahortic.1990.279.67 |issn=0567-7572}}</ref>''Algal spot'' on longan plants, like many other tropical fruits, is caused by ''[[Cephaleuros virescens]]''.<ref>{{Cite journal |last=Bache |first=Bryon |date=December 1994 |title=Compendium of Tropical Fruit Diseases, by R. C. Ploetz G. A. Zentmyer, W. T. Nishijima, K. G. Rohrbach & H. D. Ohr. viii + 88 pp. St Paul, Minnesota: American Phytopathological Society (1994). £30.00 (US) $37.00 (elsewhere) (paper back) {{text|ISBN}} 0 582 89054 162 0. |url=http://dx.doi.org/10.1017/s0021859600070520 |journal=The Journal of Agricultural Science |volume=123 |issue=3 |pages=419–420 |doi=10.1017/s0021859600070520 |issn=0021-8596}}</ref>

An oomycete disease that causes [[blight]] on leaves and foliage of a plant and affects the related lychee, ''Phytophthora palmivora'', can also appear on both longan plants and fruit,<ref name="Wang-et-al-20192">{{cite journal |last1=Wang |first1=Yan |last2=Tyler |first2=Brett M. |last3=Wang |first3=Yuanchao |date=2019-09-08 |title=Defense and Counterdefense During Plant-Pathogenic Oomycete Infection |journal=[[Annual Review of Microbiology]] |publisher=[[Annual Reviews (publisher)|Annual Reviews]] |volume=73 |issue=1 |pages=667–696 |doi=10.1146/annurev-micro-020518-120022 |issn=0066-4227 |pmid=31226025 |s2cid=195259901}}</ref> particularly in the Thailand region. When affecting longan, it can create brown spots on the fruit in an erratic fashion, and can also cause longan to drop prematurely from the plant. Early symptoms can also include a dark [[necrosis]] on the plant itself.<ref>{{Cite journal |last1=Sittigul |first1=C. |last2=Pota |first2=S. |last3=Visitpanich |first3=J. |last4=Nualbunruang |first4=P. |last5=Sookchaoy |first5=K. |date=January 2005 |title=The Brown Spot Disease of Longan in Thailand |url=http://dx.doi.org/10.17660/actahortic.2005.665.48 |journal=Acta Horticulturae |issue=665 |pages=389–394 |doi=10.17660/actahortic.2005.665.48 |issn=0567-7572}}</ref>

Stem-end rot is a disease common amongst litchi and longan, and causes browning and rot on the stem of the fruit. Longan also suffer from various decay-accelerating fungi.<ref name=":0" />

An oomycete disease that affects the related lychee, ''[[Phytophthora litchii]]'', also afflicts ''D.&nbsp;longan''.<ref name="Wang-et-al-20192" />

==Cultivation==

Currently, longan crops are grown in southern China, [[Taiwan]], northern Thailand, Malaysia, Indonesia, Cambodia, Laos, Vietnam, India, Sri Lanka, the [[Philippines]],<ref name="TK Lim" /> [[Bangladesh]],<ref name="KhatunKarim2012">{{cite journal |last1=Khatun |first1=MM |last2=Karim |first2=MR |last3=Molla |first3=MM |last4=Khatun |first4=MM |last5=Rahman |first5=MJ |year=2012 |title=Study on the physico-chemical characteristics of longan (Euphoria longana) germplasm |journal=Bangladesh Journal of Agricultural Research |volume=37 |issue=3 |pages=441–447 |doi=10.3329/bjar.v37i3.12087 |issn=0258-7122 |doi-access=free}}</ref> [[Mauritius]], the United States, and Australia.<ref name="TK Lim" />

=== Growth ===
Longan, like its sister fruit lychee, thrives in humid areas or places with high rainfall, and can grow on most types of soil that does not induce issues with water drainage.<ref name=":1">{{Cite book |url=http://dx.doi.org/10.1079/9781845936723.0000 |title=Tropical fruits, Volume 1 |date=2011 |isbn=9781845936723 |editor-last=Paull |editor-first=R. E. |doi=10.1079/9781845936723.0000 |editor2-last=Duarte |editor2-first=O.}}</ref> Ample temperatures are also instrumental in longan growth: while longan can resist small stretches of cool temperatures, they can be damaged or killed in longer stretches of temperatures as high as −2 degrees Celsius. Younger plants tend to be more vulnerable to the cold than those more mature.<ref name=":1" /><ref>{{Cite book |last=Blancke |first=Rolf |url=http://dx.doi.org/10.7591/9781501704284 |title=Tropical Fruits and Other Edible Plants of the World |date=2017-03-17 |isbn=9781501704284 |doi=10.7591/9781501704284}}</ref>

{{nutritional value
| name = Longans, raw
| image = Frutos Exóticos-LonganFruit-002.JPG
| caption = A peeled longan fruit
| kJ = 251
| water = 83 g
| protein = 1.31 g
| fat = 0.1 g
| carbs = 15.14 g
| fiber = 1.1 g
| sugars = n/a
| calcium_mg = 1
| iron_mg = 0.13
| magnesium_mg = 10
| phosphorus_mg = 21
| potassium_mg = 266
| sodium_mg = 0
| zinc_mg = 0.05
| manganese_mg = 0.052
| vitC_mg = 84
| thiamin_mg = 0.031
| riboflavin_mg = 0.14
| niacin_mg = 0.3
<!-- amino acids -->| threonine = 0.034 g
| isoleucine = 0.026 g
| leucine = 0.054 g
| lysine = 0.046 g
| methionine = 0.013 g
| phenylalanine = 0.030 g
| tyrosine = 0.025 g
| valine = 0.058 g
| arginine = 0.035 g
| histidine = 0.012 g
| alanine = 0.157 g
| aspartic acid = 0.126 g
| glutamic acid = 0.209 g
| glycine = 0.042 g
| proline = 0.042 g
| serine = 0.048 g
| source_usda = 1
| note = [https://fdc.nal.usda.gov/fdc-app.html#/food-details/169089/nutrients Link to USDA Database entry]
}}
=== Harvest ===
During harvest, pickers must climb ladders to carefully remove branches of fruit from longan trees. Longan fruit remain fresher if still attached to the branch, so efforts are made to prevent the fruit from detaching too early. Mechanical picking would damage the delicate skin of the fruit, so the preferred method is to harvest by hand. Knives and scissors are the most commonly used tools.<ref name="Muhammad Siddiq2">{{Cite book |last=Siddiq |first=Muhammad |title=Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging |publisher=John Wiley & Sons |year=2012 |via=Google Books}}</ref>

Fruit is picked early in the day to minimize water loss and to prevent high heat exposure, which would be damaging. The fruit is then placed into either plastic crates or bamboo baskets and taken to packaging houses, where the fruit undergo a series of checks for quality. The packaging houses are well-ventilated and shaded to prevent further decay. The process of checking and sorting are performed by workers instead of machinery. Any fruit that is split, under-ripe, or decaying is disposed of. The remaining healthy fruit is then prepared and shipped to markets.<ref name="BPU2">{{Cite book |last1=Menzel |first1=C. |title=Litchi and Longan: Botany, Production and Uses |last2=Waite |first2=G.K. |last3=Mitra |first3=S.K. |publisher=CAB International |year=2005 |isbn=9781845930226 |via=ProQuest ebrary}}</ref>

Many companies add preservatives to canned longan. Regulations control the preserving process. The only known preservative added to canned longan is [[sulfur dioxide]], to prevent discoloration.<ref name="BPU2" /> Fresh longan that is shipped worldwide is exposed to sulfur [[fumigation]]. Tests have shown that sulfur residues remain on the fruit skin, branches, and leaves for a few weeks. This violates many countries' limits on fumigation residue, and efforts have been made to reduce this amount.<ref name="BPU2" />

=== Distribution ===
Longan is found commonly in most of Asia, primarily in mainland China, Taiwan, Vietnam and Thailand. China, the main longan-producing country in the world, produced about {{convert|1.9|e6MT|e6ST|abbr=off}} of longan in 2015–2017, accounting for 70% of the world's longan production and more than 50% of the world's longan plots.<ref>Luo, Jun, Can-fang Zhou, and Zhong Wan. "Analysis on the development status of lychee industry in Guangdong province in 2010." Guangdong Agric Sci 4 (2011): 16-8.</ref> Vietnam and Thailand produced around {{convert|500 and 980|e3MT|e3ST|abbr=off}}, respectively.<ref>{{cite web |last=Altendorf |first=Sabine |date=July 2018 |title=MINOR TROPICAL FRUITS Mainstreaming a niche market |url=http://www.fao.org/fileadmin/templates/est/COMM_MARKETS_MONITORING/Tropical_Fruits/Documents/Minor_Tropical_Fruits_FoodOutlook_1_2018.pdf |access-date=9 September 2020 |publisher=[[FAO]]}}</ref> Like Vietnam, Thailand's economy relies heavily on the cultivation and shipments of longan as well as lychee. This increase in the production of longan reflects recent interest in exotic fruits in other parts of the world. However, the majority of the demand comes from Asian communities in North America, Europe and Australia.<ref name="BPU2" />

===Yield ===
While longan yields average out to 2 to 5 tonnes per hectare, there have been observed yields of up to 19.5 tonnes per ha in [[Israel]].<ref>{{Citation |last1=Lora |first1=Jorge |title=Genetics and Breeding of Fruit Crops in the Sapindaceae Family: Lychee (Litchi chinensis Sonn.) and Longan (Dimocarpus longan Lour.) |date=2018 |work=Advances in Plant Breeding Strategies: Fruits |pages=953–973 |editor-last=Al-Khayri |editor-first=Jameel M. |url=http://link.springer.com/10.1007/978-3-319-91944-7_23 |access-date=2022-10-05 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-91944-7_23 |isbn=978-3-319-91943-0 |last2=Pham |first2=Van The |last3=Hormaza |first3=José I. |editor2-last=Jain |editor2-first=Shri Mohan |editor3-last=Johnson |editor3-first=Dennis V.}}</ref>

Advancements in [[selective breeding]] have allowed scientists to find a strain of longan containing a "high proportion of aborted seeds" at the end of a thirty-year breeding program in 2001.<ref>{{Cite journal |last1=Huang |first1=J.S. |last2=Xu |first2=X.D. |last3=Zheng |first3=S.Q. |last4=Xu |first4=J.H. |date=August 2001 |title=Selection for Aborted-Seeded Longan Cultivars |url=http://dx.doi.org/10.17660/actahortic.2001.558.14 |journal=Acta Horticulturae |issue=558 |pages=115–118 |doi=10.17660/actahortic.2001.558.14 |issn=0567-7572}}</ref> Studies in 2015 that aimed to aid longan breeding efforts discovered that −20 degrees Celsius is the optimal temperature for long-term storage of longan pollen, a key ingredient in enabling longan breeding programs.<ref>{{Cite journal |last1=Pham |first1=V.T. |last2=Herrero |first2=M. |last3=Hormaza |first3=J.I. |date=December 2015 |title=Effect of temperature on pollen germination and pollen tube growth in longan ( Dimocarpus longan Lour.) |url=http://dx.doi.org/10.1016/j.scienta.2015.10.007 |journal=Scientia Horticulturae |volume=197 |pages=470–475 |doi=10.1016/j.scienta.2015.10.007 |bibcode=2015ScHor.197..470P |issn=0304-4238 |hdl-access=free |hdl=10261/127752}}</ref>

== Uses ==

=== Nutrition ===
Raw longan fruit is 83% water, 15% [[carbohydrate]]s, 1% [[protein (nutrient)|protein]], and contains negligible [[fat]] (table). In a {{cvt|100|g}} reference amount, raw longan supplies 60 [[calorie]]s of food energy, 93% of the [[Daily Value]] (DV) of [[vitamin C]], 11% DV of [[riboflavin]], and no other [[micronutrient]]s in appreciable quantities (table).

=== Culinary ===
The fruit is sweet, juicy, and succulent in superior agricultural varieties. The seed and the peel are not consumed. Apart from being eaten raw like other fruits, longan fruit is also often used in Asian soups, snacks, desserts, and [[sweet-and-sour]] foods, either fresh or dried, and sometimes preserved and canned in syrup. The taste is different from lychees; while longan has a drier sweetness similar to dates, lychees are often messily juicy with a more tropical, grape-like sour sweetness.

Dried longan are often used in [[Chinese cuisine]] and Chinese sweet dessert soups. In [[Chinese food therapy]] and [[Chinese medicine|herbal medicine]], it is believed to have an effect on relaxation.<ref>{{cite web|last1=Teeguarden|first1=Ron|title=Tonic Herbs That Every Qigong {{sic|Pract|ioner|nolink=y|expected=Practitioner}} Should Know, Part 2|url=https://www.qi-journal.com/herbs.asp?Name=Tonic%20Herbs%20that%20Every%20Qigong%20Practitoners%20Should%20Know%20--Part%202&-token.D=Article|website=Qi Journal|access-date=4 August 2016|archive-date=4 July 2019|archive-url=https://web.archive.org/web/20190704121122/http://www.qi-journal.com/herbs.asp?Name=Tonic%20Herbs%20that%20Every%20Qigong%20Practitoners%20Should%20Know%20--Part%202&-token.D=Article|url-status=dead}}</ref> In contrast with the fresh fruit, which is juicy and white, the flesh of dried longans is dark brown to almost black.

Once fermented, it can be made into [[longan wine]].

==See also==
*''[[Lansium parasiticum]]'', the langsat  or lanzones
*''[[Talisia esculenta]]'', a visually similar fruit from South America

==References==
{{Reflist}}

==External links==
{{Commons category|Dimocarpus longan|''Dimocarpus longan''}}
{{Wikispecies|Dimocarpus longan|''Dimocarpus longan''}}
* [http://www.fao.org/DOCREP/003/X6908E/x6908e00.htm#Contents Longan Production in Asia] from the [[Food and Agriculture Organization]] of the United Nations

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[[Category:Articles containing video clips]]
[[Category:Cantonese cuisine]]
[[Category:Chinese fruit]]
[[Category:Dimocarpus|longan]]
[[Category:Edible fruits]]
[[Category:Flora of tropical Asia]]
[[Category:Fruits originating in East Asia]]
[[Category:Han dynasty]]
[[Category:Flora of the Indomalayan realm]]
[[Category:Plants described in 1790]]
[[Category:Traditional Chinese medicine]]
[[Category:Trees of China]]
[[Category:Tropical fruit]]