An orange is a common citrus fruit. Oranges need not be orange in color; depending on climate and variety, an orange may have green patches when ripe. Some will even experience regreening, which is when an orange-colored orange loses its orange. To deal with this aesthetic problem, oranges are often dyed. Rough brownish patches are indications of abrasion against the tree, which does not affect taste.
The orange has a sweet-tart taste and is commonly peeled and eaten fresh, or squeezed for its juice. It has a thick bitter rind that is usually discarded, but can be used in cooking. The outermost layer of the rind can be scraped off to make zest, having a similar flavor to the flesh. This is the part which contains orange oil. The white part of the rind is almost always discarded as it is extremely bitter, but it does contain lots of pectin. Orange peel can be made into candied peel and used in sweet dishes.
A number of varieties of orange are now cultivated widely. The sweet orange (Citrus aurantium) was first grown in Spain, and has become the most popular variety. The sweet orange will grow to different sizes and colors due to local conditions, most commonly with ten carpels (slices) inside.
A single mutation in an orchard of sweet oranges planted at a monastery in 1820 in Brazil led to the navel orange (aka Washington, Riverside or Bahia navel). A single cutting of the original was then transplanted to California in 1870, creating a new market worldwide. The mutation caused a diploid, or twin, fruit, with a smaller orange embedded in the outer fruit near the stem. From the outside the smaller, undeveloped, twin leaves a human navel-like formation at the top of the fruit. Navel oranges are almost always seedless, and tend to be larger than the sweet orange.
The Valencia or Murcia orange is one of the sweet oranges used for juice extraction. It is a late-season fruit. It is a popular variety when navel oranges are out of season.
The blood orange (sometimes called "ruby orange" by the squeamish) has streaks of red in the fruit, and when squeezed the juice is often reddish. The mandarin is similar, but smaller and sweeter, and the scarlet navel is a variety with the same diploid mutation as the normal naval orange.
Bitter oranges are used in marmalade and as an ingredient in the liqueurs Triple sec and Curacao.
Oranges in Cooking
Orange juice is produced by juicing oranges. Brazil is the world's largest producer of orange juice, followed by Florida. Orange juice is available in fresh-squeezed or 'reconstituted' forms, and in refrigerated or pasteurised long-life bottles. The heat-treated juice is made from whole crushed oranges, including the peel, giving it a much more bitter taste than fresh-squeezed.
In the USA, orange juice is sometimes also sold in the form of frozen concentrate blocks, so a recipe may say 'one box or block frozen orange juice'. These are not available in Australia and some other countries.
Oranges are not often used in savoury cooking, but they are an important flavouring ingredient of several recipes, including orange chicken, and the French dish duck a l'orange. Orange zest, candied peel and orange juice are frequently used in making cakes and sweets.
Orange blossom honey (really "citrus honey") is produced by putting beehives in citrus groves during bloom, which also pollinates seeded citrus varieties. Orange blossom honey is highly prized, and has a distinct "orangey" flavor.