A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus Vitis.
Grapes can be eaten fresh as table grapes 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.
Grapes are a type of fruit that grow in clusters of 15 to 300, and can be crimson, black, dark blue, yellow, green, orange, and pink. “White” grapes are actually green in color, and are evolutionarily derived from the purple grape. Mutations in two regulatory genes of white grapes turn off production of anthocyanins, which are responsible for the color of purple grapes. Anthocyanins and other pigment chemicals of the larger family of polyphenols in purple grapes are responsible for the varying shades of purple in red wines. Grapes are typically an ellipsoid shape resembling a prolate spheroid.
Comparing diets among Western countries, researchers have discovered that although the French tend to eat higher levels of animal fat, the incidence of heart disease remains low in France. This phenomenon has been termed the French paradox, and is thought to occur from protective benefits of regularly consuming red wine. Apart from potential benefits of alcohol itself, including reduced platelet aggregation and vasodilation, polyphenols (e.g., resveratrol) mainly in the grape skin provide other suspected health benefits, such as:
- Alteration of molecular mechanisms in blood vessels, reducing susceptibility to vascular damage
- Decreased activity of angiotensin, a systemic hormone causing blood vessel constriction that would elevate blood pressure
- Increased production of the vasodilatorhormone, nitric oxide (endothelium-derived relaxing factor).
- Although adoption of wine consumption is not recommended by some health authorities, a significant volume of research indicates moderate consumption, such as one glass of red wine a day for women and two for men, may confer health benefits. Emerging evidence is that wine polyphenolssuch as resveratrol provide physiological benefit, whereas alcohol itself may have protective effects on the cardiovascular system. More may be seen in the article Long-term effects of alcohol.
Resveratrol is found in widely varying amounts among grape varieties, primarily in their skins and seeds, which, in muscadine grapes, have about one hundred times higher concentration than pulp. Fresh grape skin contains about 50 to 100 micrograms of resveratrol per gram.
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.