Orange (fruit)

Theorange, also calledsweet orangeto distinguish it from thebitter orange(Citrus × aurantium), is thefruitof a tree in thefamilyRutaceae. Botanically, this is the hybridCitrus×sinensis, between thepomelo(Citrus maxima) and themandarin orange(Citrus reticulata). Thechloroplastgenome, and therefore the maternal line, is that of pomelo. There are many related hybrids including of mandarins and sweet orange. The sweet orange has had its fullgenome sequenced.
The orange originated in a region encompassingSouthern China,Northeast India, andMyanmar; the earliest mention of the sweet orange was inChinese literaturein 314 BC. Orange trees are widely grown in tropical and subtropical areas for their sweet fruit. The fruit of theorange treecan be eaten fresh or processed for its juice or fragrantpeel. In 2022, 76 milliontonnesof oranges were grown worldwide, withBrazilproducing 22% of the total, followed byIndiaandChina.
Oranges, variously understood, have featured in human culture since ancient times. They first appear in Western art in theArnolfini PortraitbyJan van Eyck, but they had been depicted in Chinese art centuries earlier, as in Zhao Lingrang'sSong dynastyfan paintingYellow Oranges and Green Tangerines. By the 17th century, an orangery had become an item of prestige in Europe, as seen at theVersailles Orangerie. More recently, artists such asVincent van Gogh,John Sloan, andHenri Matisseincluded oranges in their paintings.
The orange tree is a relatively smallevergreen,floweringtree, with an average height of 9 to 10 m (30 to 33 ft), although some very old specimens can reach 15 m (49 ft).Its ovalleaves, which arealternately arranged, are 4 to 10 cm (1.6 to 3.9 in) long and havecrenulatemargins.Sweet oranges grow in a range of different sizes, and shapes varying from spherical to oblong. Inside and attached to the rind is a porous white tissue, the white, bittermesocarpor albedo (pith).The orange contains a number of distinctcarpels(segments or pigs, botanically the fruits) inside, typically about ten, each delimited by a membrane and containing manyjuice-filled vesiclesand usually a fewpips. When unripe, the fruit is green. The grainy irregular rind of the ripe fruit can range from bright orange to yellow-orange, but frequently retains green patches or, under warm climate conditions, remains entirely green. Like all other citrus fruits, the sweet orange is non-climacteric, not ripening off the tree. TheCitrus sinensisgroup is subdivided into four classes with distinct characteristics: common oranges, blood or pigmented oranges, navel oranges, and acidless oranges.The fruit is ahesperidium, a modifiedberry; it is covered by arindformed by a rugged thickening of theovary wall.
Citrustrees areangiosperms, and most species are almost entirelyinterfertile. This includesgrapefruits,lemons,limes, oranges, and manycitrus hybrids. As the interfertility of oranges and other citrus has produced numerous hybrids andcultivars, andbud mutationshave also been selected,citrus taxonomyhas proven difficult.
The sweet orange,Citrus x sinensis,is not a wild fruit, but arose indomesticationin East Asia. It originated in a region encompassingSouthern China,Northeast India,andMyanmar.The fruit was created as a cross between a non-puremandarin orangeand a hybridpomelothat had a substantial mandarin component.Since itschloroplast DNAis that of pomelo, it was likely the hybrid pomelo, perhaps a pomeloBC1 backcross, that was the maternal parent of the first orange.Based on genomic analysis, the relative proportions of the ancestral species in the sweet orange are approximately 42% pomelo and 58% mandarin.All varieties of the sweet orange descend from this prototype cross, differing only by mutations selected for during agricultural propagation.Sweet oranges have a distinct origin from the bitter orange, which arose independently, perhaps in the wild, from a cross between pure mandarin and pomelo parents.
Sweet oranges have in turn given rise to many further hybrids including thegrapefruit, which arose from a sweet orange x pomelo backcross. Spontaneous and engineered backcrosses between the sweet orange and mandarin oranges or tangerines have produced theclementineandmurcott. The ambersweet is a complex sweet orange x (Orlandotangelox clementine) hybrid.Thecitrangesare a group of sweet orange xtrifoliate orange(Citrus trifoliata) hybrids.
In Europe, theMoorsintroduced citrus fruits including the bitter orange, lemon, and lime toAl-Andalusin theIberian Peninsuladuring theArab Agricultural Revolution.Large-scale cultivation started in the 10th century, as evidenced by complex irrigation techniques specifically adapted to support orange orchards.Citrus fruits—among them the bitter orange—were introduced to Sicily in the 9th century during the period of theEmirate of Sicily, but the sweet orange was unknown there until the late 15th century or the beginnings of the 16th century, when Italian and Portuguese merchants brought orange trees into the Mediterranean area.
Shortly afterward, the sweet orange quickly was adopted as an edible fruit. It was considered a luxury food grown by wealthy people in private conservatories, calledorangeries. By 1646, the sweet orange was well known throughout Europe; it went on to become the most often cultivated of all fruit trees.Louis XIVof France had a great love of orange trees and built the grandest of all royalOrangeriesat thePalace of Versailles.At Versailles, potted orange trees in solid silver tubs were placed throughout the rooms of the palace, while the Orangerie allowed year-round cultivation of the fruit to supply the court. When Louis condemned his finance minister,Nicolas Fouquet, in 1664, part of the treasures that he confiscated were over 1,000 orange trees from Fouquet's estate atVaux-le-Vicomte.
Spanish travelers introduced the sweet orange to the American continent. On his second voyage in 1493,Christopher Columbusmay have planted the fruit onHispaniola.Subsequent expeditions in the mid-1500s brought sweet oranges to South America and Mexico, and to Florida in 1565, whenPedro Menéndez de AvilésfoundedSt Augustine.Spanish missionariesbrought orange trees to Arizona between 1707 and 1710, while theFranciscansdid the same in San Diego, California, in 1769.Archibald Menzies, the botanist on theVancouver Expedition, collected orange seeds in South Africa, raised the seedlings on board, and gave them to several Hawaiian chiefs in 1792. The sweet orange came to be grown across theHawaiian Islands, but its cultivation stopped after the arrival of theMediterranean fruit flyin the early 1900s.Floridafarmers obtained seeds from New Orleans around 1872, after which orange groves were established by grafting the sweet orange on to sour orange rootstocks.
The word "orange" derives fromSanskritनारङ्ग(nāraṅga), meaning 'orange tree'. The Sanskrit word reachedEuropean languagesthroughPersianنارنگ(nārang) and itsArabicderivativeنارنج(nāranj).The word enteredLate Middle Englishin the 14th century viaOld Frenchpomme d'orenge.Other forms includeOld Provençalauranja,Italianarancia, formerlynarancia.In several languages, the initialnpresent in earlier forms of the word dropped off because it may have been mistaken as part of an indefinite article ending in annsound. In French, for example,une norengemay have been heard asune orenge. This linguistic change is calledjuncture loss.The colorwas named after the fruit,with the first recorded use oforangeas a color name in English in 1512.
Orange flesh is 87% water, 12%carbohydrates, 1%protein, and contains negligiblefat(see table). As a 100-gram reference amount, orange flesh provides 47calories, and is a rich source ofvitamin C, providing 64% of theDaily Value. No othermicronutrientsare present in significant amounts (see table).
Oranges contain diversephytochemicals, includingcarotenoids(beta-carotene,luteinandbeta-cryptoxanthin),flavonoids(e.g.naringenin)and numerousvolatile organic compoundsproducing orangearoma, includingaldehydes,esters,terpenes,alcohols, andketones.Orange juice contains only about one-fifth thecitric acidoflimeorlemonjuice (which contain about 47 g/L).
The taste of oranges is determined mainly by the ratio of sugars to acids, whereas orange aroma derives fromvolatile organic compounds, includingalcohols,aldehydes,ketones,terpenes, andesters.Bitterlimonoidcompounds, such aslimonin, decrease gradually during development, whereas volatile aroma compounds tend to peak in mid- to late-season development.Taste quality tends to improve later in harvests when there is a higher sugar/acid ratio with less bitterness.As a citrus fruit, the orange is acidic, withpHlevels ranging from 2.9to 4.0.Taste and aroma vary according to genetic background, environmental conditions during development, ripeness at harvest, postharvest conditions, and storage duration.
Common oranges (also called "white", "round", or "blond" oranges) constitute about two-thirds of all orange production. The majority of this crop is used for juice.
The Valencia orange is a late-season fruit; it is popular when navel oranges are out of season.Thomas Rivers, an English nurseryman, imported this variety from theAzoresand catalogued it in 1865 under the name Excelsior. Around 1870, he provided trees to S. B. Parsons, aLong Islandnurseryman, who in turn sold them to E. H. Hart ofFederal Point, Florida.
Navel oranges have a characteristic second fruit at theapex, which protrudes slightly like a humannavel. They are mainly an eating fruit, as their thicker skin makes them easy to peel, they are less juicy and their bitterness makes them less suitable for juice.The parent variety was probably the Portuguese navel orange orUmbigo.The cultivar rapidly spread to other countries, but being seedless it had to be propagated bycuttingandgrafting.
TheCara Carais a type of navel orange grown mainly inVenezuela,South Africaand California'sSan Joaquin Valley. It is sweet and low in acid,with distinctively pinkish red flesh. It was discovered at theHaciendaCara Cara inValencia, Venezuela, in 1976.
Blood oranges, with an intense red coloration inside, are widely grown around the Mediterranean; there are several cultivars.The development of the red color requires cool nights.The redness is mainly due to theanthocyaninpigmentchrysanthemin(cyanidin 3-O-glucoside).
Acidless oranges are an early-season fruit with very low levels of acid. They also are called "sweet" oranges in the United States, with similar names in other countries:doucein France,sucrenain Spain,dolceormaltesein Italy,meskiin North Africa and the Near East (where they are especially popular),succariin Egypt, andlimain Brazil.The lack of acid, which protects orange juice against spoilage in other groups, renders them generally unfit for processing as juice, so they are primarily eaten. They remain profitable in areas of local consumption, but rapid spoilage renders them unsuitable for export to major population centres of Europe, Asia, or the United States.
Like most citrus plants, oranges do well under moderate temperatures—between 15.5 and 29 °C (59.9 and 84.2 °F)—and require considerable amounts of sunshine and water. They are principally grown in tropical and subtropical regions.
As oranges are sensitive tofrost, farmers have developed methods to protect the trees from frost damage. A common process is to spray the trees with water so as to cover them with a thin layer of ice, insulating them even if air temperatures drop far lower. This practice, however, offers protection only for a very short time.Another procedure involves burning fuel oil insmudge potsput between the trees. These burn with a great deal of particulate emission, so condensation of water vapor on the particulate soot prevents condensation on plants and raises the air temperature very slightly. Smudge pots were developed after a disastrous freeze in southern California in January 1913 destroyed a whole crop.
Commercially grown orange trees arepropagatedasexuallybygraftinga maturecultivaronto a suitableseedlingrootstockto ensure the sameyield, identical fruit characteristics, and resistance to diseases throughout the years. Propagation involves two stages: first, a rootstock is grown from seed. Then, when it is approximately one year old, the leafy top is cut off and abudtaken from a specificscionvariety, is grafted into its bark. The scion is what determines the variety of orange, while the rootstock makes the tree resistant to pests and diseases and adaptable to specificsoiland climatic conditions. Thus, rootstocks influence the rate of growth and have an effect on fruit yield and quality.Rootstocks must be compatible with the variety inserted into them because otherwise, the tree may decline, be less productive, or die.Among the advantages to grafting are that trees mature uniformly and begin to bear fruit earlier than those reproduced by seeds (3 to 4 years in contrast with 6 to 7 years),and that farmers can combine the best attributes of a scion with those of a rootstock.
Canopy-shaking mechanical harvesters are being used increasingly in Florida to harvest oranges. Current canopy shaker machines use a series of six-to-seven-foot-long tines to shake the tree canopy at a relatively constant  stroke and frequency.Oranges are picked once they are pale orange.
Oranges must be mature when harvested. In the United States, laws forbid harvesting immature fruit for human consumption in Texas, Arizona, California and Florida.Ripe oranges, however, often have some green or yellow-green color in the skin.Ethylenegas is used to turn green skin to orange. This process is known as "degreening", "gassing", "sweating", or "curing".Oranges are non-climactericfruits and cannot ripen internally in response to ethylene gas after harvesting, though they will de-green externally.
Commercially, oranges can be stored by refrigeration in controlled-atmosphere chambers for up to twelve weeks after harvest. Storage life ultimately depends on cultivar, maturity, pre-harvest conditions, and handling.At home, oranges have a shelf life of about one month, and are best stored loose.
The first major pest that attacked orange trees in the United States was the cottony cushion scale (Icerya purchasi), imported from Australia to California in 1868. Within 20 years, it wiped out the citrus orchards around Los Angeles, and limited orange growth throughout California. In 1888, the USDA sent Alfred Koebele to Australia to study thisscale insectin its native habitat. He brought back with him specimens of an Australianladybird,Novius cardinalis(the Vedalia beetle), and within a decade the pest was controlled. This was one of the first successful applications ofbiological pest controlon any crop.Theorange dogcaterpillar of the giant swallowtail butterfly,Papilio cresphontes, is a pest of citrus plantations in North America, where it eats new foliage and can defoliate young trees.
Citrus greening disease, caused by the bacteriumLiberobacter asiaticum, has been the most serious threat to orange production since 2010. It is characterized by streaks of different shades on the leaves, and deformed, poorly colored, unsavory fruit. In areas where the disease is endemic, citrus trees live for only five to eight years and never bear fruit suitable for consumption.In the western hemisphere, the disease was discovered in Florida in 1998, where it has attacked nearly all the trees ever since. It was reported in Brazil by Fundecitrus Brasil in 2004.As from 2009, 0.87% of the trees in Brazil's main orange growing areas (São Paulo and Minas Gerais) showed symptoms of greening, an increase of 49% over 2008.The disease is spread primarily bypsyllidplant lice such as the Asian citrus psyllid (Diaphorina citriKuwayama), an efficientvectorof the bacterium.Foliar insecticides reduce psyllid populations for a short time, but also suppress beneficial predatory ladybird beetles. Soil application ofaldicarbprovided limited control of Asian citrus psyllid, while drenches ofimidaclopridto young trees were effective for two months or more.Management of citrus greening disease requires an integrated approach that includes use of clean stock, elimination of inoculum via voluntary and regulatory means, use of pesticides to control psyllid vectors in the citrus crop, and biological control of the vectors in non-crop reservoirs.
Greasy spot, afungal diseasecaused by the ascomyceteMycosphaerella citri, produces leaf spots and premature defoliation, thus reducing the tree's vigour and yield.AscosporesofM. citriare generated inpseudotheciain decomposing fallen leaves.
In 2022, world production of oranges was 76 milliontonnes, led byBrazilwith 22% of the total, followed by India, China, and Mexico.TheUnited States Department of Agriculturehas establishedgradesfor Florida oranges, primarily for oranges sold as fresh fruit.In the United States, groves are located mainly inFlorida,California, andTexas.The majority of California's crop is sold as fresh fruit, whereas Florida's oranges are destined to juice products. TheIndian Riverarea of Florida produces high quality juice, which is often sold fresh and blended with juice from other regions, because Indian River trees yield sweet oranges but in relatively small quantities.
Oranges, whose flavor may vary fromsweettosour, are commonly peeled and eaten fresh raw as a dessert.Orange juiceis obtained by squeezing the fruit on a special tool (ajuicerorsqueezer) and collecting the juice in a tray or tank underneath. This can be made at home or, on a much larger scale, industrially.Orange juice is a traded commodity on theIntercontinental Exchange.Frozen orange juice concentrate is made from freshly squeezed and filtered juice.
Oranges are made intojamin many countries; in Britain, bitterSeville orangesare used to makemarmalade. Almost the whole Spanish production is exported to Britain for this purpose. The entire fruit is cut up and boiled with sugar; the pith contributespectin, which helps the marmalade to set. The first recipe was by an Englishwoman,Mary Kettilby, in 1714. Pieces of peel were first added byJanet KeillerofDundeein the 1790s, contributing a distinctively bitter taste.Orange peel contains the bitter substanceslimoneneandnaringin.
Zestis scraped from thecoloured outer part of the peel, and used as a flavoring and garnish in desserts andcocktails.
Sweetorange oilis aby-productof the juice industry produced by pressing the peel. It is used for flavoring food and drinks; it is employed in the perfume industry and inaromatherapyfor itsfragrance. The oil consists of approximately 90%D-limonene, asolventused in household chemicals such as wood conditioners for furniture and—along with other citrus oils—detergents and hand cleansers. It is an efficient cleaning agent with a pleasant smell, promoted for being environmentally friendly and therefore preferable to petrochemicals. It is, however, irritating to the skin and toxic to aquatic life.
Oranges have featured in human culture since ancient times. The earliest mention of the sweet orange inChinese literaturedates from 314 BC.Larissa Pham, inThe Paris Review, notes that sweet oranges were available in China much earlier than in the West. She writes that Zhao Lingrang's fan paintingYellow Oranges and Green Tangerinespays attention not to the fruit's colour but the shape of the fruit-laden trees, and that Su Shi's poem on the same subject runs "You must remember, / the best scenery of the year, / Is exactly now, / when oranges turn yellow and tangerines green."
The scholar Cristina Mazzoni has examined the multiple uses of the fruit in Italian art and literature, fromCatherine of Siena's sending of candied oranges toPope Urban, toSandro Botticelli's setting of his paintingPrimaverain an orange grove. She notes that oranges symbolised desire and wealth on the one hand, and deformity on the other, while in the fairy-stories of Sicily, they have magical properties.Pham comments that theArnolfini PortraitbyJan van Eyckcontains in a small detail one of the first representations of oranges in Western art, the costly fruit perhaps traded by the merchant Arnolfini himself.By the 17th century,orangerieswere added to great houses in Europe, both to enable the fruit to be grown locally and for prestige, as seen in theVersailles Orangeriecompleted in 1686.
The DutchPost-ImpressionistartistVincent van Goghportrayed oranges in paintings such as his 1889Still Life of Oranges and Lemons with Blue Glovesand his 1890A Child with Orange, both works late in his life. The American artist of theAshcan School,John Sloan, made a 1935 paintingBlond Nude with Orange, Blue Couch, whileHenri Matisse's last painting was his 1951Nude with Oranges; after that he only made cut-outs.