Citrus Fruits

Citrus is a genus of flowering trees and shrubs in the rue
family, Rutacae. These plants produce citrus fruit, including
important crops like oranges, lemons, grapefruit, pomelo,
pomegranates, peaches, kiwi and limes.
The most recent research indicates an origin in Australia,
New Caledonia and New Guinea. Some researchers believe
that citrus originated from part of Southeast Asia, and
it is in this region that some commercial species such as
oranges, mandarins, and lemons originated. Citrus fruit has
been cultivated in an ever-widening area since ancient times.
At various times, citrus plants were thought to be native
to Asia (where they were first domesticated), Europe,
and Florida. But the European oranges (such as the bitter
orange) were originally brought from India at around the
time of Alexander the Great, and the “native” oranges of
Florida originated with the Spanish Conquistadors. The
lemon reached Europe during the time of classical Rome.
The large citrus fruit of today evolved originally from
small, edible berries over millions of years. Citrus plants
diverged from a common ancestor about 15 million years
ago. Within the last few thousand years, all common
citrus fruits (sweet oranges, lemons, grapefruit, limes,
and so on) were created by crossing the original species.
Citrus fruit are notable for their fragrance, partly
due to flavonoids and limonoids contained in the rind, and
most are juice laden. The juice contains a high quantity
of citric acid giving them their sharp flavour. The genus
is commercially important as many species are cultivated
for their fruit, which is eaten fresh, squeezed for juice,
or preserved in marmalades and pickles.
They are also good sources of vitamin C and flavonoids.
The content of vitamin C in the fruit depends on the species,
variety and mode of cultivation. Fruits produced in organic
agriculture are richer in vitamin C than those produced in
conventional agriculture.
Many citrus fruits, such as oranges, tangerines,
grapefruit, and clementines are generally eaten fresh. They
are typically peeled and can be easily split into segments.
Grapefruit is more commonly halved and eaten out of the
skin with a spoon. Orange and grapefruit juices are also very
popular breakfast drinks.
More acidic citrus, such as lemons and limes, are generally
not eaten on their own. Meyer lemons can be eaten as they
are both sweet and sour. Lemons and limes are also used
as garnishes or in cooked dishes. Their juice is used as an
ingredient in a variety of dishes; it can commonly be found
in salad dressings and squeezed over cooked meat, fish or
vegetables.
The rind and oil of the fruit is generally very bitter,
especially when cooked, and so is often combined with sugar.
The fruit pulp can vary from sweet and tart to extremely
sour. Marmalade, a condiment derived from cooked orange
and lemon, can be especially bitter, but is usually sweetened
to cut the bitterness and produce a jam-like result. Lemon or
lime is commonly used as a garnish for water, soft drinks, or
cocktails. Citrus juices, rinds, or slices are used in a variety
of mixed drinks. The colourful outer skin of some citrus
fruits, known as zest, is used as a flavouring in cooking; the
white inner portion of the peel, the pith, is usually avoided
due to its bitterness.
Historically, rations of oranges were given to British
soldiers on long ocean voyages to prevent scurvy. Scurvy is
caused by vitamin C deficiency, so the high vitamin C content
in oranges made them perfect for preventing the disease.