Monday 20 June 2016

Grape

A grape is a fruiting berry of the deciduous woody vines of the botanical genus Vitis.Grapes can be eaten raw or they can be used for making wine, jam, juice, jelly, grape seed extract, raisins, vinegar, and grape seed oil. Grapes are a non-climacteric type of fruit, generally occurring in clusters.

The cultivation of the domesticated grape began 6,000–8,000 years ago in the Near East. Yeast, one of the earliest domesticated microorganisms, occurs naturally on the skins of grapes, leading to the innovation of alcoholic drinks such as wine. The earliest archeological evidence for a dominant position of wine-making in human culture dates from 8,000 years ago in Georgia. The oldest known winery was found on the territory of modern Armenia, dating to around 4000 BC. By the 9th century AD the city of Shiraz was known to produce some of the finest wines in the Middle East. Thus it has been proposed that Syrah red wine is named after Shiraz, a city in Persia where the grape was used to make Shirazi wine. Ancient Egyptian hieroglyphics record the cultivation of purple grapes, and history attests to the ancient Greeks, Phoenicians, and Romans growing purple grapes for both eating and wine production. The growing of grapes would later spread to other regions in Europe, as well as North Africa, and eventually in North America.

In North America, native grapes belonging to various species of the Vitis genus proliferate in the wild across the continent, and were a part of the diet of many Native Americans, but were considered by European colonists to be unsuitable for wine. Vitis vinifera cultivars were imported for that purpose.

Commercially cultivated grapes can usually be classified as either table or wine grapes, based on their intended method of consumption: eaten raw (table grapes) or used to make wine (wine grapes). While almost all of them belong to the same species, Vitis vinifera, table and wine grapes have significant differences, brought about through selective breeding. Table grape cultivars tend to have large, seedless fruit (see below) with relatively thin skin. Wine grapes are smaller, usually seeded, and have relatively thick skins (a desirable characteristic in winemaking, since much of the aroma in wine comes from the skin). Wine grapes also tend to be very sweet: they are harvested at the time when their juice is approximately 24% sugar by weight. By comparison, commercially produced "100% grape juice", made from table grapes, is usually around 15% sugar by weight.

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 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 being cultivars of Vitis vinifera. There are currently more than a dozen varieties of seedless grapes. Several, such as Einset Seedless, Benjamin Gunnels's Prime seedless grapes, Reliance, and Venus, have been specifically cultivated for hardiness and quality in the relatively cold climates of northeastern United States and southern Ontario.

An offset to the improved eating quality of seedlessness is the loss of potential health benefits provided by the enriched phytochemical content of grape seeds .

Grape juice is obtained from crushing and blending grapes into a liquid. The juice is often sold in stores or fermented and made into wine, brandy, or vinegar. Grape juice that has been pasteurized, removing any naturally occurring yeast, will not ferment if kept sterile, and thus contains no alcohol. In the wine industry, grape juice that contains 7–23% of pulp, skins, stems and seeds is often referred to as "must". In North America, the most common grape juice is purple and made from Concord grapes, while white grape juice is commonly made from Niagara grapes, both of which are varieties of native American grapes, a different species from European wine grapes. In California, Sultana (known there as Thompson Seedless) grapes are sometimes diverted from the raisin or table market to produce white juice.

Biochemical and preliminary clinical studies have demonstrated potential biological properties of grape seed oligomeric procyanidins. For example, laboratory tests indicated a potential anticancer effect from grape seed extract. According to the American Cancer Society, "there is very little reliable scientific evidence available at this time that drinking red wine, eating grapes, or following the grape diet can prevent or treat cancer in people".

Grape seed oil from crushed seeds is used in cosmeceuticals and skincare products for perceived health benefits. Grape seed oil contains tocopherols (vitamin E) and high contents of phytosterols and polyunsaturated fatty acids such as linoleic acid, oleic acid, and alpha-linolenic acid.

The consumption of grapes and raisins presents a potential health threat to dogs. Their toxicity to dogs can cause the animal to develop acute renal failure (the sudden development of kidney failure) with anuria (a lack of urine production) and may be fatal.

Grape therapy, also known as ampelotherapy (from Ancient Greek ἄμπελος (ampelos), meaning "vine"), is a form of naturopathic medicine or alternative medicine that involves heavy consumption of grapes, including seeds, and parts of the vine, including leaves. Although there is some limited evidence of positive benefits from the consumption of grapes for health purposes, extreme claims, such as its ability to cure cancer, have been widely derided as “quackery”.

Grape juice, because of its non-alcoholic content, is commonly used by those Christians who oppose the partaking of alcoholic beverages, as the "cup" or "wine" in the Lord's Supper.

The Catholic Church uses wine in the celebration of the Eucharist because it is part of the tradition passed down through the ages starting with Jesus Christ at the Last Supper, where Catholics believe the consecrated bread and wine literally become the body and blood of Jesus Christ, a dogma known as transubstantiation. Wine is used (not grape juice) both due to its strong Scriptural roots, and also to follow the tradition set by the early Christian Church. The Code of Canon Law of the Catholic Church (1983), Canon 924 says that the wine used must be natural, made from grapes of the vine, and not corrupt. In some circumstances, a priest may obtain special permission to use grape juice for the consecration, however this is extremely rare and typically requires sufficient impetus to warrant such a dispensation, such as personal health of the priest.

Although alcohol is permitted in Judaism, grape juice is sometimes used as an alternative for kiddush on Shabbat and Jewish holidays, and it has the same blessing as wine. Many authorities maintain that grape juice must be capable of turning into wine naturally in order to be used for kiddush. Common practice, however, is to use any kosher grape juice for kiddush.

No comments: