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The citron is a fragrant fruit with the botanical name Citrus medica L., which applies to both the Swingle and Tanaka systems. It is a prominent member in the genus Citrus, belonging to the Rutaceae, or Rue, family, sub-family Aurantoideae. Its different names—Citrus Media, Median Apple etc.—were influenced by the Theophrastus, who considered it being native to Media, Persia or Assyria. However, those names are rarely in use today.
The citron is unlike more common citrus fruit like the lemon or orange. While the most popular citrus species are peeled in order to consume its pulpy and juicy segments, – the citron's pulp is very dry with little value compared to the orange. Moreover, its main content is the thick white rind which adheres to the segments, and cannot be separated from them easily. Thus, from ancient through medieval times the citron was used mainly for the fragrance of its outer peel or for medicine derived from it that was used to combat against seasickness, pulmonary troubles, intestinal ailments, and other disorders. Citron juice with wine was considered an effective antidote to poison. The essential oil of the peel was regarded as an antibiotic.
The most important part of the citron is the peel which is a fairly important article in international trade. The fruits are halved, depulped, immersed in seawater or ordinary salt water to ferment for about 40 days, the brine being changed every 2 weeks; rinsed, put in denser brine in wooden barrels for storage and for export. After partial de-salting and boiling to soften the peel, it is candied in a strong sugar solution. The candied peel is sun-dried or put up in jars for future use. Candying is done mainly in England, France and the United States. The candied peel is widely employed in the food industry, especially as an ingredient in fruit cake, plum pudding, buns, sweet rolls and candy. 
Today there is an uprising market for the citron is the United States for the soluble fiber which is found in its thick rind, also called albedo. The citron is also used by Jews for a religious ritual during the Feast of Tabernacles, by whom it is called Etrog.
The citron has many similar names in diverse languages, e.g. cederat, cedro, etc. Most confusing is the French and Swedish language, in which the false friend "citron" refers to a lemon in English.
Additional recommended knowledge
Origin and distribution
Today, authorities agree that all citrus species are native to Southeast Asia where they are found wild and at an uncultivated form; the fascinating story about how they spread to the Mediterranean has been reported by many (Calabrese, 1998; Chapot, 1975; Tolkowsky, 1938). 
The citron especially sounds to be native to India bordering Burma, where it is found in valleys at the foot of the Himalaya Mountains, and in the Western Ghauts.  It is still considered that by the time of Theophrastus, the citron was mostly cultivated in the Persian Gulf on its way to the Mediterranean basin, where it was cultivated during the later centuries in different areas as described by Erich Isaac. . Many mention the role of Alexander the Great and his armies, to be responsible for the spread of the citron westward, reaching the European countries like Greece and Italy.
The citron is already mentioned in the Torah for the ritual use during the Feast of Tabernacles (Lev. 23:40). It is considered that the Jews brought it along by The Exodus from Egypt, where archeological evidence found it to be in since the times of Thutmosis III.
The opinion that the citron was the forbidden fruit in the Hesperides of Eden is not providing any geographical positioning, since the exact orientation of the Hesperidies is unclear. Besides, there are enough reasons to conclude that it was in the Far East for e.g. India or Yemen, where the citron is likely to have originated.
Description and Variation
The citron fruit is usually ovate or oblong, narrowing up till the stylar end. However, the citron's fruit shape is highly variable, due to the big quantity of albedo which forms independently according to the fruits' position on the tree, twig orientation and many other factors. This could also be the reason of its being protuberant, forming a "v" shape after the end of the segments pointing to the stylar end.
The rind is leathery, furrowed, and adherent. The inner portion thick, white and fleshy, the outer uniformly thin, and very fragrant. The pulp is usually acidic, but also sweet and even pulpless varieties are found.
Most citron varieties contain a large number of seeds. The monoembryonic seeds are white colored with dark innercoat and red-purplish chalazal spot for the acidic varieties, and colorless or white for the sweet ones. Some citron varieties are also distinct with their persistent style, which is highly appreciated by the Jewish community.
Citrons are also prized for their beauty. The nicer ones are those with medium sized oil bubbles at the outer surface, which are medially distant each to another. Some of them are ribbed and faintly warted in outer surface, adding life and attraction to its beauty. There is also a fingered citron variety called Buddha's Hand.
The color changes from green when unripe, till yellow-orange when ripe or overripe. The citron does not fall off the tree and could reach 8-10 pounds (4-5 kg) if not picked off timely or even early . However they should be picked off before the winter as the branches might break, or bend to the ground which may cause numerous fungal diseases for the tree.
The slow-growing shrub or small tree reaches a height of about 8 to 15 ft (2.4-4.5 m); it has irregular straggling branches and stiff twigs and long spines in the leaf axils. The evergreen leafs are pale-green and lemon scented with slightly serrate edges, ovate-lanceolate or ovate elliptic 2 1/2 to 7 inch long. Petioles are usually wingless or with minor wings. The flowers are generally unisexual providing self-pollination, but some male individuals could be found due to pistil abortion. Flowers of the acidic varieties are purplish tinted from outside, but the sweet ones are white-yellowish.
The citron tree is very vigorous with almost no dormancy, blooming several times a year, therefore fragile and extremely sensitive. The farmer's choice is to graft it onto foreign rootstock, but since this practice is forbidden by Jewish Law, the progeny will not be kosher for the Jewish ritual.
The citron was always considered as a Jewish symbol, and is found on various Hebrew antiques and archeological foundlings.
The Citron in antiquity
The citron has been cultivated since ancient times, predating cultivation of other citrus species. Despite its minor importance today being hardly consumed as is, it seems that in different times it played a big role in life. We could see that from the way how it was described by numerous writings and poets across centuries. It is suggested that when the other citrus species arrived, they pushed the citron off the road, since most of its benefits could nearly by found in the lemon, which is much easier to cultivate.
The following is from the writings of Theophrastus
"In the east and south there are special plants... i.e. in Media and Persia there are many types of fruit, between them there is a fruit called Median or Persian Apple. The tree has a leaf similar to and almost identical with that of the andrachn (Arbutus andrachne L.), but has thorns like those of the apios (the wild pear, Pyrus amygdaliformis Vill.) or the oxyacanthos (the fire thorn, Cotoneaster pyracantha Spach.), except that they are white, smooth, sharp and strong.
"The fruit is not eaten, but is very fragrant, as is also the leaf of the tree; and the fruit is put among clothes, it keeps them from being moth-eaten. It is also useful when one has drunk deadly poison, for when it is administered in wine; it upsets the stomach and brings up the poison. It is also useful to improve the breath, for if one boils the inner part of the fruit in a dish or squeezes it into the mouth in some other medium, it makes the breath more pleasant.
"The seed is removed from the fruit and sown in the spring in carefully tilled beds, and it is watered every fourth or fifth day. As soon the plant is strong it is transplanted, also in the spring, to a soft, well watered site, where the soil is not very fine, for it prefers such places.
"And it bears its fruit at all seasons, for when some have gathered, the flower of the others is on the tree and is ripening others. Of the flowers I have said those which have a sort of distaff [meaning the pistil] projecting from the middle are fertile, while those which do not have this are sterile. It is also sown, like date palms, in pots punctured with holes.
"This tree, as has been remarked, grows in Media and Persia."
Later with about 400 years it was also described by Pliny the Elder, who was calling it nata Assyria malus.
"The Assyrian fruit, which some call Median, is an antidote for poisons. Its leaf is like that of the andrachn (Arbutus andrachne L.), but with thorns running between. The fruit is notable for the fact that it is not eaten and has a strong odor, as also do the leaves, which impregnates clothes stored with them and keeps away harmful insects.
"The tree itself bears fruit continuously; some dropping off, others ripening, and still others budding.
"People have tried to introduce the tree into their land in clay vessels because of its medicinal efficacy, providing breathing for the roots by making holes in the vessels; …but except among Media and in Persia, it has refused to grow.
"This is the fruit whose pips we have related Parthian nobles boiled in foods in order to eliminate bad breath. No other tree is so highly praised in Media."
Genetics and Hybridization
There is molecular evidence that all cultivated citrus species arose by hybridization among the ancestral types, which are the citron, pummelo, mandarin and papedas. The citron is believed to be the purest of them all since it is usually fertilized by self-pollination, it hardly excepts foreign pollen, and is therefore considered to be the male parent rather than a female one.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Citron". A list of authors is available in Wikipedia.|