Citrus fruit from the orange tree. There are three major types of oranges: Sweet (Valencia, Mediterranean, and Navel), Loose-skinned (Mandarin, King), and Bitter (Seville, Bergamot). Bitter oranges are used in marmalades.
The orange (specifically, the sweet orange) is the fruit of the citrus species Citrus × sinensis in the family Rutaceae. The fruit of the Citrus sinensis is called sweet orange to distinguish it from that of the Citrus aurantium, the bitter orange. The orange is a hybrid, possibly between pomelo (Citrus maxima) and mandarin (Citrus reticulata), cultivated since ancient times.
Probably originated in Southeast Asia, oranges were already cultivated in China as far back as 2500 BC. Between the late 15th century and the beginnings of the 16th century, Italian and Portuguese merchants brought orange trees in the Mediterranean area. The Spanish introduced the sweet orange to the American continent in the mid-1500s.
Orange trees are widely grown in tropical and subtropical climates for its sweet fruit, which can be eaten fresh or processed to obtain juice, and for its fragrant peel. They have been the most cultivated tree fruit in the world since 1987, and sweet oranges account for approximately 70% of the citrus production. In 2010, 68.3 million tonnes of oranges were grown worldwide, particularly in Brazil and in the US states of California and Florida.
The origin of the term orange is presumably the Sanskrit word for “orange tree” (नारङगम्, nāraṅga), whose form has changed over time, after passing through numerous intermediate languages. The fruit is known as “Chinese apple” in several modern languages. Some examples are Dutch sinaasappel (literally, “China’s apple”) and appelsien, or Low German Apfelsine. In English, however, Chinese apple usually refers to the pomegranate.
Oranges, whose flavour can vary from sweet to sour, are commonly peeled and eaten fresh or squeezed for juice. The thick bitter rind is usually discarded, but can be processed into animal feed by desiccation, using pressure and heat. It is also used in certain recipes as a food flavouring or garnish. The outermost layer of the rind can be thinly grated with a zester to produce orange zest. Zest is popular in cooking because it contains the oil glands and has a strong flavour similar to that of the orange pulp. The white part of the rind, including the pith, is a source of pectin and has nearly the same amount of vitamin C as the flesh.
Although not as juicy or tasty as the flesh, orange peel is edible and has higher contents of vitamin C and more fibre. It also contains citral, an aldehyde that antagonizes the action of vitamin A. Orange peel has been consumed particularly in environments where resources are scarce and therefore maximum nutritional value must be obtained with the minimum generation of waste (for example, on a submarine). Since large concentrations of pesticides have been found in orange peels, some organizations recommend the consumption of the peel of organically grown and processed oranges alone, where chemical pesticides or herbicides would not have been used.
Products made from oranges
- Orange juice is obtained by squeezing the fruit on a special tool (a juicer or squeezer) and collecting the juice in a tray underneath. This can be made at home or, on a much larger scale, industrially. Brazil is the largest producer of orange juice in the world, followed by the US, where it is one of the commodities traded on the New York Board of Trade.
- Frozen orange juice concentrate is made from freshly squeezed and filtered orange juice.
- Sweet orange oil is a by-product of the juice industry produced by pressing the peel. It is used for flavouring food and drinks and also in the perfume industry and aromatherapy for its fragrance. Sweet orange oil consists of approximately 90% D-limonene, a solvent used in various 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. D-limonene is, however, classified from slightly toxic to humans to very toxic to marine life in different countries.
Although once thought to cause renal cancer in rats, limonene is now considered a natural chemopreventive agent in humanssince there is no evidence for its carcinogenicity or genotoxicity. The Carcinogenic Potency Project estimates that D-limonene causes human cancer on a level roughly equivalent to that caused by exposure to caffeic acid via dietary coffee intake, whereas the International Agency for Research on Cancer (IARC) classifies it under Class 3, which means it is not classifiable as to its carcinogenicity to humans.
- The orange blossom, which is the state flower of Florida, is highly fragrant and traditionally associated with good fortune. It has long been popular in bridal bouquets and head wreaths.
- Orange blossom essence is an important component in the making of perfume.
- Orange blossom petals can also be made into a delicately citrus-scented version of rosewater, known as “orange blossom water” or “orange flower water”. It is a common ingredient in French and Middle Eastern cuisines, especially in desserts and baked goods. In some Middle Eastern countries, drops of orange flower water are added to disguise the unpleasant taste of hard water drawn from wells or stored in qullahs (traditional Egyptian water pitchers made of porous clay). In the United States, orange flower water is used to make orange blossom scones and marshmallows.
- In Spain, fallen blossoms are dried and used to make tea.
- Orange blossom honey (or citrus honey) is obtained by putting beehives in the citrus groves while trees bloom. By this method, bees also pollinate seeded citrus varieties. This type of honey has an orangey taste and is highly prized.
- Marmalade is usually made with Seville oranges. All parts of the fruit are used: the pith and pips (separated and placed in a muslin bag) are boiled in a mixture of juice, slivered peel, sliced-up flesh, sugar and water to extract their pectin, which helps the conserve to set.
- Orange peel is used by gardeners as a slug repellent.
- Orange leaves can be boiled to make tea.
- Orangewood sticks are used as cuticle pushers in manicures and pedicures, and as spudgers for manipulating slender electronic wires.
- Orangewood is used in the same way as mesquite, oak and hickory for seasoning grilled meat.