The orange, also called sweet orange is the fruit of a tree in the family Rutaceae.
Botanically, this is the hybrid Citrus × sinensis, between the pomelo (Citrus maxima) and the mandarin orange (Citrus reticulata).
Orange trees are widely grown in tropical and subtropical areas for their sweet fruit.
The fruit of the orange tree can be eaten fresh or processed for its juice or fragrant peel.
In 2022, 76 million tons of oranges were grown worldwide, with Brazil producing 22% of the total, followed by India and China.
The orange tree is a relatively small evergreen, flowering tree, with an average height of 9 to 10 m (30 to 33 ft).
Sweet oranges grow in a range of different sizes, and shapes.
Inside the orange it is attached to the rind a porous white tissue, the white, bitter mesocarp or albedo (pith).
The orange contains a number of distinct carpels (segments) typically about ten, each delimited by a membrane and containing many juice-filled vesicles and usually a few pips.
When unripe, the fruit is green.
Like all other citrus fruits, the sweet orange is non-climacteric, not ripening off the tree.
The Citrus sinensis group is subdivided into four classes with distinct characteristics: common oranges, blood or pigmented oranges, navel oranges, and acidless oranges.
The orange fruit is a hesperidium, a modified berry.
It is covered by a rind formed by a rugged thickening of the ovary wall.
Citrus trees are angiosperms, and most species are almost entirely interfertile.
This includes grapefruits, lemons, limes, oranges, and many citrus hybrids.
The interfertility of oranges and other citrus has produced numerous hybrids and cultivars.
The sweet orange, Citrus x sinensis, created as a cross between a non-pure mandarin orange and a hybrid pomelo that had a substantial mandarin component.
Sweet oranges have in turn given rise to many further hybrids including the grapefruit, which arose from a sweet orange x pomelo backcross.
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, called orangeries.
Oranges, raw, Nutritional value per 100 g (3.5 oz) Energy 197 kJ (47 kcal) Carbohydrates 11.75 g Sugars 9.35 g Dietary fiber 2.4 g Fat 0.12 g Protein 0.94 g Vitamins and minerals Water 86.75 g
Orange flesh is 87% water, 12% carbohydrates, 1% protein, and contains negligible fat.
As a 100-gram reference amount, orange flesh provides 47 calories, and is a rich source of vitamin C, providing 64% of the Daily Value.
No other micronutrients are present in significant amounts.
Oranges contain diverse phytochemicals, including carotenoids (beta-carotene, lutein and beta-cryptoxanthin), and flavonoids (e.g. naringenin), and numerous volatile organic compounds producing orange aroma, including aldehydes, esters, terpenes, alcohols, and ketones.
Orange juice contains only about one-fifth the citric acid of lime or lemon juice, which contain about 47 g/L).
Octyl acetate, is a volatile compound contributing to the fragrance of oranges
The taste of oranges is determined by the ratio of sugars to acids, whereas orange aroma derives from volatile organic compounds, including alcohols, aldehydes, ketones, terpenes, and esters.
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, with pH levels ranging from 2.9 to 4.0.
Common oranges constitute about two-thirds of all orange production.
The majority of this crop is used for juice.
Valencia
The Valencia orange is a late-season fruit; it is popular when navel oranges are out of season.
Navel orange
Navel oranges have a characteristic second fruit at the apex, which protrudes slightly like a human navel.
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.
Blood oranges, with an intense red coloration inside, are widely grown around the Mediterranean; with several cultivars.
The redness is mainly due to the anthocyanin pigment chrysanthemin.
Acidless oranges also are called “sweet” oranges in the United States.
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.
Like most citrus plants, oranges do well under moderate temperatures—between 15.5 and 29 °C (59.9 and 84.2 °F) are principally grown in tropical and subtropical regions.
As oranges are sensitive to frost, farmers have developed methods to protect the trees from frost damage: spraying the trees with water so as to cover them with a thin layer of ice, insulating them even if air temperatures drop far lower.
Another procedure involves burning fuel oil in smudge pots put between the trees.
Commercially grown orange trees are propagated asexually by grafting a mature cultivar onto a suitable seedling rootstock to ensure the same yield, identical fruit characteristics, and resistance to diseases throughout the years.
The scion is what determines the variety of orange, while the rootstock makes the tree resistant to pests and diseases and adaptable to specific soil and climatic conditions.
Thus, rootstocks influence the rate of growth and have an effect on fruit yield and quality.
Oranges must be mature when harvested.
Ethylene gas is used to turn green skin to orange.
Oranges are non-climacteric fruits and cannot ripen internally in response to ethylene gas after harvesting, though they will de-green externally.
Oranges can be stored by refrigeration in controlled-atmosphere chambers for up to twelve weeks after harvest.
At home, oranges have a shelf life of about one month, and are best stored loose.
Production of oranges – 2022 Country Production (millions of tonnes) Brazil 16.9 India 10.2 China 7.6 Mexico 4.8 Egypt 3.4 United States 3.1 World 76.4
The majority of California’s orange crop is sold as fresh fruit, whereas Florida’s oranges are destined to juice products.
Oranges, whose flavor may vary from sweet to sour, are commonly peeled and eaten fresh raw as a dessert.
Orange juice is obtained by squeezing the fruit on a special tool and collecting the juice in a tray or tank underneath.
Oranges are made into jam in many countries.
Sweet orange oil is a by-product of the juice industry produced by pressing the peel.
It is used for flavoring food and drinks; it is employed in the perfume industry and in aromatherapy for its fragrance.
The oil consists of approximately 90% D-limonene, a solvent used 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.