* Orange (fruit), common name for citrus fruit of several trees. Orange trees seldom exceed 9 m (30 ft) in height. The leaves are oval and glossy, and the flowers are white and fragrant. The orange fruit has several easily separated sections, each containing several seeds and many juice cells. These sections are covered by a leathery skin that contains numerous oil glands. Three essential oils are obtained from oranges: oil of orange, obtained from the rind of the fruit and used principally as a flavoring agent; oil of petigrain, obtained from the leaves and twigs and used in perfumery; and oil of neroli, obtained from the blossoms and used in flavorings and perfumes. Oranges are cultivated in warm regions. In the United States, the principal orange-producing states are Florida, California, Texas, and Arizona. About 20 percent of the total crop of oranges is sold as whole fruit; the remainder is used in preparing frozen and canned orange juice, extracts, and preserves.
* Oranges belong to the rue family and are closely related to the other citrus fruits. Fresh oranges and orange juice are noted for their nutritional value. An orange, or a small glass of orange juice, contains the recommended daily allowance of vitamin C.
Orange trees grow in tropical, subtropical, and Mediterranean-type climate areas throughout the world. Native to southeastern Asia, orange trees have been cultivated for more than 3,000 years. They have been raised in Europe since the 15th century. Introduced to the New Worldby Spaniards, orange trees have been grown in Florida since 1565 and in California since 1769.
* Scientific classification: Oranges belong to the genus Citrus, of the family Rutaceae.
* Orange blossoms, particularly those from sour oranges, are a source of neroli oil, used in cologne. The orange blossom is the state flower of Florida and the traditional wedding flower.
* Orange peels are an important source of oils and pectin. The oils are extracted by cold pressing and by steam distillation. They are used in beverages, candies, perfumes, cosmetics, and soaps. Dissolving orange oil in alcohol produces orange extract, a flavoring for foods such as candy, ice cream, and bakery products. Oils from the rinds of sour oranges are added to medicines and give flavor to curacao, a liquer.
* Undamaged oranges that are not suitable for other uses are often made into marmalade. In the processes used in the United States, the base of marmalade is a jelly made from oranges and either lemons or grapefruits. The other citrus fruits add flavor and enough pectin (the substance that makes jelly set) to make a solid jelly. To the jelly are added finely sliced orange peels. Bitter English marmalades are made from sour oranges.
* Citrus trees are monoecious - both sexes are in the same blossom. In some varieties the pollen and ovules are always imperfect so self-fertilisation rarely occurs. These trees continue to develop fruit but it will be virtually seedless. Varieties which like their own pollen will bear fruit full of incestuos seeds.
* Oranges are prone to numerous pests and diseases and require frequent spraying. This has been so effective in Florida that lightning now kills as many trees as any disease.
* Hybrid Oranges: Most citrus trees consist of two parts. The upper framework is one kind of citrus and the roots and trunks are another. The parts meet in a visible line round the trunk. All the lemon trees in California are grown on orange tree root. Extensive crossing results in multi-fruit trees, with up to six different fruits lemons, limes, grapefruit, tangerines, oranges and kumquats.
* Pectin, extracted from orange skins, is an important ingredient of commercial and home made jellies. Orange peels, treated with sugar and dried, are made into candy and fruit pieces for bakery products. Waste orange skins and pulp are usually dried and sold for livestock feed.
* Ripe oranges do not fall from the tree. They are carefully clipped from the tree with clippers to avoid breaking the skin; if they are to be used for concentrate, however, the oranges may be snapped off. Once they are picked, oranges donot ripen further, though the skin color of some varieties becomes more orange. The skins of oranges are sometimes artificially tinted or are treated with gas or chemicals to stimulate the natural processes that cause the peel to change from green to orange as it ripens.
* Oranges and orange trees are attacked by many insects, worms, fungi, viruses, and single-celled organisms. Root and foot rot, caused by fungi, and viral diseses, such as tristeza and psorosis, are some of the more troublesome. Treatment for diseases and pests includes dusting and spraying, fumigating, and burning infected trees.
Picked oranges are rotted by fungi and bacteria wherever the skin has been broken. Damage from these parasites has been lessened by careful picking and handling, by fumigation, and by storing and shipping the fruit under refrigeration.
* From 70 to 80 per cent of the orange crop of the United States is made into juice, syrups, canned pieces for salads, and other products such as marmalade and preserved orange peel. Most of the remainder of the crop - the oranges of best appearance and quality - is sold as fresh fruit for home use.
* Experimental orange-picking machines include combs, shakers & blowers which deliver gusts of wind swinging the oranges like pendulums till they fall. One of the machine's chief drawbacks is that it can only be used on trees where the whole crop ripens simultaneously. An experienced person can pick a tree in about an hour - picking 20,000 oranges a day.
* Citrus fruits are easily crossbred. Products of the crosses are reproduced by grafting. The Temple orange is one variety that is the result of a cross between sweet oranges and tangerines. It has the easily peeled skin of a tangerine and the size of an orange. The Honey Murcott and the King orange are other hybrids of sweet oranges and tangerines.
* Orange trees require a large amont of warm weather to produce high-quality fruit. They are, however, raised successfully for commerce only in areas having a Mediterranean-type climate (hot, dry summers and cool, wet winters) or a humid, subtropical climate (warm, wet summers and cool, drier winters). Temperatures of 25'F. (-4'C.), such as occur during frosts, damage the fruit and young twigs. Temperatures of 20'F. (-7'C) severely damage or kill th trees. Frost damage is lessened by use of orchard heaters or by circulating air with wind machines.
Being relatively shallow-rooted, orange trees can be raised in as little as four feet (1.2 m) of well-drained soil. Where rainfall is insufficient, there are irrigated at intervals through the year.
Soil and climate requirements for orange production are met in various parts of the world, including the southeastern and southwestern United States, the Mediterranean countries, Japan, and Mexico. The leading orange-producing states are Florida and California; smaller amounts come from Arizona and Texas.
* -3'C is the critical minimum temperature for the health of orange trees and their fruit. Oil, coal, wood and old tyres are burnt between the trees on frosty nights. Some groves have giant fans to mix the cold low air with the warmer air above. Another method of heating is to turn on the water sprinklers. As long as freezing water is in contact with the fruit the temperature cannot fall below 0'C. The danger is that the accumulating weight of ice on the branches will break them unless there is a rapid thaw.
* Oranges have to be washed after picking to remove the residue of the sprays. This removes their natural surface wax, without which they quickly shrivel up, so most oranges are polished with wax polish after washing.
* Orange trees are broad-leaved, shallow-rooted evergreens. They grow to between 20 and 30 feet (6 and 9 m) high. The narrow, pointed leaves have prominent mid-ribs and are of a glossy, dark-green color. Blunt spines are found on the twigs. The numerous, white, single blossoms are fragrantly scented. In the United States they bloom from late February to early April. Insects pollinate the blossoms of wild trees; most commercial varieties do not need pollination.
* Orange trees grown from seeds are unsuited for commercial orchards because of thorniness and slowness in producing fruit. Commercial oranges are therefore propagated chiefly by budding (a form of grafting in which a bud from a tree that produces high-quality fruit is grafted onto a rootstock). Budding also allows the multiplication of seedless varieties such as the navel oranges. The rootstocks used are seedlings of citrus fruits which are often more resistant to cold and to certain diseases than are the buds. The rootstocks give their resistance to the tree. Some species commonly used for rootstocks are the trifoliate orange, rough lemon, tangerine, sour orange, and the sweet orange itself.
* * In Europe and the Americas, the commercially important species are the sweet orange and the sour orange. Sweet oranges are used mainly for juice and as fresh fruit. Sour oranges are raised chiefly in Europe and are used primarily for products such as marmalade and essential oils. The tangerine, or mandarin, was originally an Oriental orange. The bergamot orange, is a citrus species that produces inedible fruit. The trifoliate, or deciduos, orange is a frost-resistant tree often grown as an ornamental plant. It produces inedible fruit and does not belong to the citrus genus.
Varieties that ripen at different times and have few or no seeds have been developed from sweet oranges. In Florida the Hamlin, an early-ripening orange, is picked from late September to January. The Pineapple, a mid-season orange, is picked in Florida from late October to late January. The Valencia, a late orange in Florida, is picked there from late December tp late May. In California and Arizona, early, mid-season, and alte oranges are also raised. The Valencias raised in California and Arizona do not receive enough heat in one year to ripen. They are picked from February to December of the year after the flowers bloom.
The number of seeds in an orange is determined by the number of fertile ovules (immature seeds) the fruit produces, by the fertility of the pollen, and by the thoroughness of pollination. Oranges are classed in three groups: seedless, commercially seedless, and seedy. The navel orange produces no seeds (with rare exceptions) because it produces few fertile ovules and no fertile pollen. Its name, navel, was suggested by the raised area on the skin caused by its production of additional sections internally. Commercially seedless oranges are the Valencia and the Hamlin, both of which have fertile pollen and a few fertile ovules. They usually produce a few seeds. Seedy oranges have fertile pollen and many fertile ovules.
* Like the other citrus fruits, the fruit of the orange tree is classified as a type of berry called hesperidium. Oranges are roughly spherical in shape, and average three inches (7.5 cm) in diameter. The skin or peel, is a spongy rind containing many oil glands. A ripe orange ranges in color from greenish-yellow to orange-red.
The fruit is divided into many sections seperated by papery membranes. The pulp in each section consists of many spindle-shaped juice sacs. The pulp is orange or red colored when ripe. In most areas of the United States, the fruit ripens between September and May.
* Oranges to be processed for juice are sorted to removethe unsuitable fruits. They are carefully washed and graded for size as soon after picking as possible. Then they are sent to juice extracting machines that remove the juice by squeezing the orange or by reaming out the pulp. The juice is seperated from the oils of the skin in the process of squeezing or by centrifugation.
Juice that is to be used fresh is pasteurized and put into bottles or cans. If it is to be frozen, th ejuice is concentrated at a low temperature in a high vacuum. At this time some unconcentrated, fresh juice is added to the concentrate to improve its flavor. The concentrate is then canned and frozen at -10'F. (-23'C.). The entire process, from juice extraction to storage, takes about 30 minutes.
In similar ways, other concentrates are made for dehydrated orange juice and for syrups used in the manufacture of candies and carbonated beverages.
* Many ripe oranges remain green on the outside. This used to reduce their market value, so most oranges are now 'gassed' in chambers with an atmosphere of Ethylene. This is not quite so unnatural as it sounds; many fruits including bananas give off ethylene and green oranges left in a room full of bananas would turn orange.
* The sweet orange is Citrus sinesis; the sour orange, C. aurantium. The trifoliate orange is Poncirus trifoliata.
* The navel orange derives its name from the navel like opening in the top of each orange, containing a small 'foetal' orange with 5 or 6 pithy segments.