Grapefruit

Grapefruit
Pink grapefruit
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Sapindales
Family:	Rutaceae
Genus:	Citrus
Species:	C. × paradisi
Binomial name
Citrus × paradisi Macfad.

The grapefruit (Citrus × paradisi) is a subtropical citrus tree known for its sour to semi-sweet somewhat bitter fruit . Grapefruit is a hybrid originating in Barbados as an accidental cross between two introduced species, sweet orange (C. sinensis) and pomelo or shaddock (C. maxima), both of which were introduced from Asia in the seventeenth century.^[1] When found, it was named the “forbidden fruit”;^[2] and it has also been misidentified with the pomelo.^[3]

The grapefruit's name alludes to clusters of the fruit on the tree, which often appear similar to grapes.^[4]

Description

Grapefruit growing in the grape-like clusters from which their name derives.

The evergreen grapefruit trees usually grow to around 5–6 meters (16–20 ft) tall, although they can reach 13–15 m (43–49 ft). The leaves are glossy dark green, long (up to 15 centimeters (5.9 in)) and thin. It produces 5 cm (2 in) white four-petaled flowers. The fruit is yellow-orange skinned and generally an oblate spheroid in shape; it ranges in diameter from 10–15 cm (3.9–5.9 in). The flesh is segmented and acidic, varying in color depending on the cultivars, which include white, pink and red pulps of varying sweetness (generally, the redder varieties are sweeter). The 1929 US Ruby Red (of the Redblush variety) has the first grapefruit patent.^[5]

History

One ancestor of the grapefruit was the Jamaican sweet orange (Citrus sinensis), itself an ancient hybrid of Asian origin; the other was the Indonesian pomelo (C. maxima). One story of the fruit's origins is that a certain "Captain Shaddock"^[6] brought pomelo seeds to Jamaica and bred the first fruit.^[7] However, it probably originated as a naturally occurring hybrid between the two plants some time after they had been introduced.^[1]

The hybrid fruit, then called "the forbidden fruit", was first documented in 1750 by a Welshman, Rev. Griffith Hughes, who described specimens from Barbados in The Natural History of Barbados.^[8][9] Currently, the grapefruit is said to be one of the "Seven Wonders of Barbados".^[10]

The grapefruit was brought to Florida by Count Odet Philippe in 1823 in what is now known as Safety Harbor. Further crosses have produced the tangelo (1905), the Minneola tangelo (1931), and the oroblanco (1984).

The grapefruit was known as the shaddock or shattuck until the 19th century.^[11] Its current name alludes to clusters of the fruit on the tree, which often appear similar to grapes.^[4] Botanically, it was not distinguished from the pomelo until the 1830s, when it was given the name Citrus paradisi. Its true origins were not determined until the 1940s. This led to the official name being altered to Citrus × paradisi, the "×" identifying its hybrid origin.^[12][13]

Kimball Chase Atwood

An early pioneer in the American citrus industry was Kimball Chase Atwood, a wealthy entrepreneur who founded the Atwood Grapefruit Co. in the late 19th century. The Atwood Grove became the largest grapefruit grove in the world, with a yearly output of 80,000 boxes of fruit.^[14] It was there that pink grapefruit was first discovered in 1906.^[15]

Ruby Red

The 1929 Ruby Red patent was associated with real commercial success, which came after the discovery of a red grapefruit growing on a pink variety. The Red grapefruit, starting with the Ruby Red, has even become a symbolic fruit of Texas, where white “inferior” grapefruit were eliminated and only red grapefruit were grown for decades. Using radiation to trigger mutations, new varieties were developed to retain the red tones which typically faded to pink.^[16] The Rio Red variety is the current (2007) Texas grapefruit with registered trademarks Rio Star and Ruby-Sweet, also sometimes promoted as "Reddest" and "Texas Choice". The Rio Red is a mutation bred variety which was developed by treatment of bud sticks with thermal neutrons.^[17] Its improved attributes of mutant variety are fruit and juice color, deeper red, and wide adaptation.^[18]

Star Ruby

The Star Ruby is the darkest of the red varieties. Developed from an irradiated Hudson grapefruit,^[19] it has found limited commercial success because it is more difficult to grow than other varieties.^[20][21]

Varieties

The varieties of Texas and Florida grapefruit include: Oro Blanco, Ruby Red, Pink, Thompson, White Marsh, Flame, Star Ruby, Duncan, and Pummelo HB.^[22]

• 
  Grapefruit.
• 
  1750 Engraving of The Forbidden Fruit Tree by Georg Dionysius Ehret
• 
  Grapefruit in growth
• 
  Pink grapefruit
• 
  Half peeled 'Indian' cultivar

Production

Grapefruit and pomelo output in 2005

China is the top producer of grapefruit and pomelo followed by The United States and Mexico.

Top eleven grapefruit (inc. pomelos) producers — 2012
Country	Production (metric tons)	Footnote
People's Republic of China	3,800,000	F
United States	1,046,890
Mexico	415,471
Thailand	328,000	F
South Africa	304,559
Israel	246,618
Turkey	243,267
Argentina	200,000	F
India	200,000	F
Sudan	196,000
Ghana	192,000
World	8,040,038	A
No symbol = official figure, P = official figure, F = FAO estimate, * = Unofficial/Semi-official/mirror data, C = Calculated figure A = Aggregate (may include official, semi-official or estimates); Source: Food And Agricultural Organization of United Nations: Economic And Social Department: The Statistical Division

Colors and flavors

Grapefruit mercaptan

Grapefruit comes in many varieties. One way to differentiate between varieties is by the flesh color of fruit they produce.^[23] The most popular varieties cultivated today are red, white, and pink hues, referring to the internal pulp color of the fruit. The family of flavors range from highly acidic and somewhat sour to sweet and tart.^[23] Grapefruit mercaptan, a sulfur-containing terpene, is one of the substances which has a strong influence on the taste and odor of grapefruit, compared with other citrus fruits.^[24]

Drug interactions

Grapefruit and grapefruit juice have been found to interact with numerous drugs and in many cases result in adverse direct and/or side effects (if dosage is not carefully adjusted.)^[25]

This happens in two very different ways. In the first it is postulated that the bioactivation effect is from bergamottin, a natural furanocoumarin in both grapefruit flesh and peel that ""inhibits"" the CYP3A4 enzyme, (among others from the P450 enzyme family responsible for metabolizing 90% of drugs). The action of this CYP3A4 enzyme itself ""inhibits"" the metabolism of many medications with the double negative inhibition actually increasing the drug's effects and side-effects.^[26][27] If the drug's breakdown for removal is lessened, then the level of the drug in the blood can become too high or stay too long, leading to adverse effects.^[27]

The other effect is that grapefruit can block the absorption of drugs in the intestine.^[27] If the drug is not absorbed, then not enough of it is in the blood to have a therapeutic effect.^[27] Each affected drug has either a specific increase of effect or decrease.

One whole grapefruit, or a glass of 200 mL (6.8 US fl oz) of grapefruit juice can cause drug overdose toxicity.^[28] Drugs which are incompatible with grapefruit are typically labeled on the container or package insert.^[27] People taking drugs can ask their health care provider or pharmacist questions about grapefruit / drug interactions.^[27]

Nutritional properties

Grapefruit is a rich source (>20% of the Daily Value, DV in a 100 gram serving) of vitamin C,^[23][29] contains the fiber pectin,^[30] and the pink and red hues contain the beneficial antioxidant lycopene.^[23][31] Studies have shown grapefruit helps lower cholesterol,^[23][32] and there is evidence that the seeds have antioxidant properties.^[33] Grapefruit forms a core part of the "grapefruit diet", the theory being that the fruit's low glycemic index is able to help the body's metabolism burn fat.^[34]

Although grapefruit seed extract (GSE) is promoted as a plant-based preservative by some natural personal care manufacturers, studies have shown that the apparent antimicrobial activity associated with GSE preparations is merely due to contamination with synthetic preservatives such as parabens.^{[35][36][37][38][39]}

There is a popular myth that grapefruits contain high amounts of spermidine, a simple polyamine that may be related to aging. The myth probably relies on the confusion between spermidine and putrescine. While citrus fruits show high amounts of putrescine, they contain very little spermidine.^[40]

Grapefruit sweets

In Costa Rica, especially in Atenas, grapefruit are often cooked to remove their sourness, rendering them as sweets; they are also stuffed with dulce de leche, resulting in a dessert called toronja rellena (stuffed grapefruit). In Haiti, grapefruit is used primarily for its juice (jus de Chadèque), but is also used to make jam (confiture de Chadèque).^[41][42]

Other uses

Grapefruit has also been investigated in cancer medicine pharmacodynamics. Its inhibiting effect on the metabolism of some drugs may allow smaller doses to be used, which can help to reduce costs.^[43]

Grapefruit relatives

Grapefruit is a pummelo backcross, a hybrid of pummelo × sweet orange, with sweet orange itself being a pummelo × mandarin hybrid.

The grapefruit is itself a parent to many hybrids:

• A Tangelo is any hybrid of a tangerine and either a pomelo or a grapefruit.
  • 'Minneola': Duncan grapefruit × Dancy tangerine^[44]
  • 'Orlando' (formerly 'Take'): Bowen grapefruit × Dancy tangerine(pollen parent)^[45]
    • Fairchild is a Clementine × Orlando hybrid
  • 'Seminole': Bowen grapefruit × Dancy tangerine^[45]
  • 'Thornton': tangerine × grapefruit, unspecified^[45]
  • 'Ugli': mandarin × grapefruit, probable (wild seedling)^[45]
  • 'Nova' is a second-generation hybrid: Clementine × Orlando tangelo cross^[45]
• The Oroblanco and Melogold grapefruits are hybrids between pummelo (Citrus maxima) and the grapefruit.

The grapefruit's cousins include:

• Common sweet orange: pummelo × mandarin hybrid
• Bitter orange: a different pummelo × mandarin hybrid
• Mandelos: pummelo × mandarine (Citrus maxima).
• Hyuganatsu may also be a pumelo hybrid

See also

References

External links

Look up grapefruit in Wiktionary, the free dictionary.

Wikimedia Commons has media related to Citrus paradisi.

• Data related to Citrus paradisi at Wikispecies
• Grapefruit from "Fruits of warm climates" by Julia F. Morton.
• https://web.archive.org/web/20150525230639/http://www.properhealthyliving.com/14-amazing-health-benefits-of-grapefruit-juice/