Grapes are the fruit that grow on a woody grape vine. The grapevine belongs to the family Vitaceae. Grapes grow in clusters of 6 to 300, and can be black, blue, golden, green, purple-red and white. They can be eaten raw or used for making grape juice, jelly, wine, and grape seed oil.
Raisins are the dried fruit of the grapevine, and the name actually comes from the French word for "grape". Wild grapevines are often considered a nuisance weed, as they cover other plants with their usually rather aggressive growth.
Grapevines are used as food plants by the larvae of some Lepidoptera species - see list of Lepidoptera which feed on grapevines.
Many species of grapevines exist and these include:
- Vitis vinifera, the European winemaking grapevine. Native to virtually all of mainland Europe.
- Vitis labrusca, the North American table and grape juice grapevines, sometimes used for wine. Native to Canada and the Eastern U.S.
- Vitis riparia, a wild vine of North America, sometimes used for winemaking and for jam. Native to the entire Eastern U.S. north to Quebec.
- Vitis rotundifolia, the muscadines, used for jams and wine. Native to the Southeastern U.S. from Delaware to the Gulf of Mexico.
- Vitis aestivalis, the variety Norton (AKA Cynthiana) is used for winemaking
- Vitis lincecumii (also called Vitis aestivalis or Vitis lincecumii), Vitis berlandieri (also called Vitis cinerea var. helleri), Vitis cinerea, Vitis rupestris are used for making hybrid grapevines and for pest-resistant rootstocks.
- Vitis arizonica A desert grapevine found in the southwestern US that is hardy against extremes of temperature. Can be used for wines.
- Vitis californica A grapevine important to the California wine industry for its rootstock which is able to withstand pests and cooler weather. Native to California and Oregon.
- Vitis vulpina Frost Grape. Native to the Midwest east to the coast up through New York.
There are many varieties of grapevines; most are cultivars of V. vinifera.
Hybrids also exist, and these are primarily crosses between V. vinifera and one or more varieties of V. labrusca, V. riparia or V. aestivalis. Hybrids tend to be less susceptible to frost and disease (notably phylloxera), but wine from some hybrids may have a little of the characteristic "foxy" odor of labrusca.
The sea grape Coccoloba uvifera is actually a member of the Buckwheat family Polygonaceae and is native to the lands of the Caribbean Sea.
According to the "Food and Agriculture Organization"(FAO), 75866 square kilometres of the world is 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 list of top wine-producers shows the corresponding areas dedicated to grapes for wine making:
- 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
- China 1,780 km²
Sources: FAO, Organisation Internationale de la Vigne et du Vin (pdf).
Researchers,such as Marty Mayo, comparing diets in western countries have discovered that although the French tend to eat higher levels of animal fat, surprisingly the incidence of heart disease remains low in France. They named this phenomenon the French Paradox. Many scientists now believe the reason is the greater consumption of red wine in France. Something in the grape helps to lower cholesterol levels in the body and thus slows the build up of deposits in the arteries. Compounds such as resveratrol (a member of the polyphenol family) have been discovered in grapes and these have been positively linked to fighting cancer, heart disease, degenerative nerve disease and other ailments. Doctors do not recommend excessive consumption of red wine, but three or four glasses a week is beneficial and encouraged.
Although many people incorrectly assume that red grapes are more beneficial to the health, in fact grapes of all colors offer comparable benefits. Red wine however does offer some health benefits not found in white wine, because many of the beneficial compounds are found in the skins of the grapes, and only red wine is fermented with the skins.
Another common misconception is that white wine has to be made from green grapes. In fact, it can be made from green or red varieties. Red wines are made from red grapes, but the colouration is a result of including the skins in the fermentation process.
Raisins, currants, and sultanas
A raisin is any dried grape. A currant is a dried Zante grape, originally grown near Corinth. A sultana was originally a dried Sultana grape; however, modern product includes Thompson Seedless grapes treated with sulphur dioxide and lightly heated. This makes them more golden in colour and taste sweeter.
Grape seed extract
The seeds in grapes are known to contain procyanidolic oligomers, also known as PCOs. Researchers have concluded that PCOs strengthen blood vessels, and improve blood circulation. Grape seed extract may help slow aging, prevent heart disease, deter cancer, lessen allergy symptoms, and eye strain, and fight certain skin diseases. In recent studies grape extract has also been shown to lessen cellulite, and lower cholesterol and blood pressure levels. The use of grape seed extract is available in forms such as: liquid, tablet, and capsule. Grape seed extract has not yet been shown to have any negative effects on consumers.
Seedlessness in Grapes
Seedlessness is a highly desirable trait 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 cultivars get it from one of three sources: 'Thompson Seedless', 'Russian Seedless', and 'Black Monukka'. All are members of Vitis vinifera.