This article is about the fruits of the genus
Vitis. For the European
grapevine, see
Vitis vinifera.
For the computer programming environment, see
GRAPE.
A grape is the non-climacteric fruit that grows on
the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten
raw or used for making jam, juice, jelly, vinegar, wine and grape seed oil.
Description
Grapes grow in clusters of 6 to 300, and can be black, blue, golden, green, purple, red, pink, brown, peach or white. White
grapes are evolutionarily derived from the red grape. Mutations in two regulatory genes turn off production of anthocyanin, which is responsible for the color of the red grape.[1].
Grapevines
-
Most grapes come from cultivars of Vitis
vinifera, the European grapevine native to the Mediterranean and Central Asia. Minor amounts of fruit and wine come
from American and Asian species such as :
The sea grape Coccoloba uvifera is
actually a member of the Buckwheat family Polygonaceae and is native to the islands
of the Caribbean Sea.
Distribution and production
According to the "Food and Agriculture Organization" (FAO), 75,866 square kilometres of the world are dedicated to grapes.
Approximately 71% of world grape production is used for wine, 27% as fresh fruit, and 2% as dried fruit. A portion of grape
production goes to producing grape juice to be used as a sweetener for fruits canned "with no added sugar" and "100% natural".
The area dedicated to vineyards is increasing by about 2% per year.
The following table of top wine-producers shows the corresponding areas dedicated to grapes for wine making:
| Country |
Area Dedicated |
| Spain |
11,750 km² |
| France |
8,640 km² |
| Italy |
8,270 km² |
| Turkey |
8,120 km² |
| United States |
4,150 km² |
| Iran |
2,860 km² |
| Romania |
2,480 km² |
| Portugal |
2,160 km² |
| Argentina |
2,080 km² |
| Australia |
1,642 km² |
Sources: FAO, Organisation Internationale de la Vigne et du Vin (pdf), Australian Wine and Brandy
Corporation.
Seedless grapes
Seedlessness is a highly desirable subjective quality in table grape selection, and seedless cultivars now make up the
overwhelming majority of table grape plantings. Because grapevines are vegetatively
propagated by cuttings, the lack of seeds does not present a problem for reproduction. It is, however, an issue for
breeders, who must either use a seeded variety as the female parent or rescue embryos early in development using tissue culture techniques.
There are several sources of the seedlessness trait, and essentially all commercial cultivators get it from one of three
sources: Thompson Seedless, Russian Seedless, and Black Monukka. All are cultivars of Vitis
vinifera.
Contrary to the improved eating quality of seedlessness is the loss of potential health benefits provided by the enriched
phytochemical content of grape seeds[2][3]. (see Health Claims
below)
Raisins, currants, and sultanas
- See also: Dried vine fruit
In most of Europe, dried grapes are universally referred to as 'raisins' or the local equivalent. In the UK, three different
varieties are recognised, forcing the EU to use the term "Dried vine fruit" in official
documents.
A raisin is any dried grape. While raisin is a French loanword, the word in French refers to the fresh fruit; grappe (whence the English grape is
derived) refers to the bunch (as in une grappe de raisins).
A currant is a dried Zante grape, the name
being a corruption of the French raisin de Corinthe (Corinth grape). Note also that currant has come to refer also to the blackcurrant and redcurrant, two berries completely unrelated to
grapes.
A sultana was originally a raisin made from a specific type of grape of
Turkish origin, but the word is now applied to raisins made from common grapes and chemically treated to resemble the traditional
sultana.
Health claims
Ripe table grapes ready to be eaten
-
Comparing diets among western countries, researchers have discovered that although the French tend to eat higher levels of
animal fat, surprisingly the incidence of heart disease remains low in France, a
phenomenon named the French Paradox thought to occur from protective benefits of
regularly consuming red wine. Apart from potential benefits of alcohol itself, including reduced platelet aggregation and vasodilation[4], polyphenols (e.g., resveratrol) mainly in the grape skin provide other suspected health benefits, such as[5]
Doctors do not recommend excessive consumption of red wine, but one glass a day for women and two for men may confer health
benefits[6].
Compounds such as resveratrol (a polyphenol
antioxidant) have been discovered in grapes and these have been positively linked to fighting cancer, heart disease, degenerative nerve disease and other ailments. Synthesized
by many plants, resveratrol apparently serves antifungal and other defensive properties.
Dietary resveratrol has been shown to modulate the metabolism of lipids and to inhibit oxidation
of low-density lipoproteins and aggregation of platelets.[7]
Resveratrol is found in wide amounts among grape varieties, primarily in their skins and seeds which, in muscadine grapes, have about one hundred times higher concentration than pulp[8]. Fresh grape skin contains about 50 to 100 micrograms of resveratrol per
gram[9].
Anthocyanins tend to be the main polyphenolics in red grapes whereas flavan-3-ols (e.g., catechins) are the more abundant phenolic in white
varieties[10]. Total phenolic content, an index of dietary
antioxidant strength, is higher in red varieties due almost entirely to anthocyanin density in red grape skin compared to absence
of anthocyanins in white grape skin[11]. It is these
anthocyanins that are attracting the efforts of scientists to define their properties for human health[12]. Phenolic content of grape skin varies with cultivar, soil composition, climate, geographic origin, and cultivation practices or exposure to diseases, such
as fungal infections.
Red wine offers health benefits moreso than white because many beneficial compounds are present
in grape skin, and only red wine is fermented with skins. The amount of fermentation time a wine spends in contact with grape
skins is an important determinant of its resveratrol content.[2] Ordinary
non-muscadine red wine contains between 0.2 and 5.8 mg/L
[13], depending on the grape variety, because it is
fermented with the skins, allowing the wine to absorb the resveratrol. By contrast,
a white wine contains lower phenolic contents because it is fermented after removal of skins.
Wines produced from muscadine grapes may contain more than 40 mg/L, an exceptional phenolic
content.[14] [3]. In muscadine skins, ellagic acid, myricetin, quercetin, kaempferol, and
trans-resveratrol are major phenolics[15]. Contrary to
previous results, ellagic acid and not resveratrol is the major phenolic in muscadine grapes.
Since the 1980s, biochemical and medical studies have demonstrated powerful antioxidant
properties of grape seed oligomeric proanthocyanidins[16]. Together with tannins, polyphenols and polyunsaturated fatty acids, these seed constituents display inhibitory activities against several experimental disease
models, including cancer, heart failure and other
disorders of oxidative stress[17][18]. Grape seed oil from crushed seeds is used for many perceived health benefits.
See also
External links
Wikimedia Commons has media related to:
References
- ^ Walker AR, Lee E, Bogs J, McDavid DA,
Thomas MR, Robinson SP (2007). "White grapes arose through the mutation of two similar and adjacent regulatory genes". Plant
J 49 (5): 772–85. PMID 17316172.
- ^ Shi J, Yu J, Pohorly JE, Kakuda Y. (2003 Winter). "Polyphenolics in grape seeds-biochemistry and functionality.". J Med Food. 2003
Winter;6(4):291-9.. Retrieved on 2007-08-16.
- ^ Parry J, Su L, Moore J, Cheng Z, Luther M, Rao JN, Wang JY, Yu LL.
(2006-05-31). "Chemical compositions, antioxidant capacities, and antiproliferative activities of selected
fruit seed flours.". J Agric Food Chem. 2006 May 31;54(11):3773-8.. Retrieved on 2007-08-16.
- ^ Providência R. (2006). Cardiovascular protection from alcoholic drinks:
scientific basis of the French Paradox. Rev Port Cardiol. 2006 Nov;25(11):1043-58. Abstract.
- ^ Opie LH, Lecour S. (2007). The red wine hypothesis: from concepts to
protective signalling molecules. Eur Heart J. 2007 Jul;28(14):1683-93. Abstract.
- ^ Alcohol. Harvard School of Public Health
- ^ Chan, W. K., & Delucchi, A. B. (2000). Resveratrol, a red wine
constituent, is a mechanism-based inactivator of cytochrome P450 3A4. Life Sci 67 (25): 3103-3112. Abstract.
- ^ LeBlanc, MR (2005). Cultivar, Juice Extraction, Ultra Violet Irradiation and Storage Influence the
Stilbene Content of Muscadine Grapes (Vitis Rotundifolia Michx.). PhD Dissertation, Louisiana State University
- ^ Li X, Wu B, Wang L, Li S. (2006). Extractable amounts of trans-resveratrol
in seed and berry skin in Vitis evaluated at the germplasm level. J Agric Food Chem. 2006 Nov 15;54(23):8804-11. Abstract.
- ^ Cantos E, Espín JC, Tomás-Barberán FA. (2002). Varietal differences among
the polyphenol profiles of seven table grape cultivars studied by LC-DAD-MS-MS. J Agric Food Chem. 2002 Sep 25;50(20):5691-6.
Abstract.
- ^ Cantos E, Espín JC, Tomás-Barberán FA. (2002). Varietal differences among
the polyphenol profiles of seven table grape cultivars studied by LC-DAD-MS-MS. J Agric Food Chem. 2002 Sep 25;50(20):5691-6.
Abstract.
- ^ Gross PM (2007). Scientists zero in on health benefits of berry pigments.
Natural Products Information Center 2007 Jul 9. [1]
- ^ Gu X, Creasy L, Kester A, et al., Capillary electrophoretic determination
of resveratrol in wines. J Agric Food Chem 47:3323-3277, 1999
- ^ Ector BJ, Magee JB, Hegwood CP, Coign MJ. Resveratrol Concentration in
Muscadine Berries, Juice, Pomace, Purees, Seeds, and Wines. http://www.ajevonline.org/cgi/content/abstract/47/1/57
- ^ Pastrana-Bonilla E, Akoh CC, Sellappan S, Krewer G. (2003). Phenolic
content and antioxidant capacity of muscadine grapes. J Agric Food Chem. 2003 Aug 27;51(18):5497-503. Abstract.
- ^ Bagchi D, Bagchi M, Stohs SJ, Das DK, Ray SD, Kuszynski CA, Joshi SS,
Pruess HG. (2000-08-07). "Free radicals and grape seed proanthocyanidin extract: importance in human health and
disease prevention.". Toxicology. 2000 Aug 7;148(2-3):187-97.. Retrieved on 2007-08-16.
- ^ Agarwal C, Singh RP, Agarwal R. (2002-11-23). "Grape seed extract induces apoptotic death of human prostate carcinoma DU145 cells via
caspases activation accompanied by dissipation of mitochondrial membrane potential and cytochrome c release.".
Carcinogenesis. 2002 Nov;23(11):1869-76.. Retrieved on 2007-08-16.
- ^ Bagchi D, Sen CK, Ray SD, Das DK, Bagchi M, Preuss HG, Vinson JA.
(2003-02-01). "Molecular mechanisms of cardioprotection by a novel grape seed proanthocyanidin
extract.". Mutat Res. 2003 Feb-Mar;523-524:87-97.. Retrieved on 2007-08-16.
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