Widely popular, grapes are regarded in many cultures as “the queen of fruits,” since centuries. These tiny berries are the storehouse of numerous health promoting phyto-nutrients such as poly phenolic antioxidants, vitamins, and minerals. No wonder why many of us include them as an integral part of our diet, be it in the form of fresh table fruits, juice, or in salads!
Botanically, they are small round berries; grow in clusters on a perennial and deciduous woody vine of the genus: Vitis. Grapes are native to Europe and Mediterranean regions but now widely cultivated all around the world.
In structure, each berry features semi-translucent flesh encased in a smooth, thin skin. Some varieties contain edible seeds, while others are seedless. The color to the fruit is because of the presence of poly-phenolic pigments in them. Red or purple berries are rich in anthocyanins while white-green berries contain more of tannins, especially, catechin. Interestingly, these antioxidant compounds are densely concentrated on the skin and seeds!
The three main species of grapes grown around the world are; European (Vitis vinifera), North American (Vitis labrusca and Vitis rotundifolia), and French hybrids.
- Some of popular green cultivars are Thompson seedless, sugarone, and calmeria.
- Red varieties include emperor, red globe, cardinal, and flame seedless.
- Concord and zinfandel are some of flavorful blue-black cultivars.
Commercially, many cultivars of grapes are grown for different purposes either eaten as table fruit, fresh or dried (raisin, currant, sultana) or in wine production.
Health benefits of grapes
- Grapes are rich in polyphenolic phytochemical compound resveratrol. Resveratrol is one of the powerful anti-oxidant, which has been found to play a protective role against cancers of colon and prostate, coronary heart disease (CHD), degenerative nerve disease, Alzheimer’s disease and viral/ fungal infections.
- Resveratrol reduces stroke risk by altering the molecular mechanisms in the blood vessels. It does so firstly by reducing susceptibility of blood vessel damage through decreased activity of angiotensin (a systemic hormone causing blood vessel constriction that would otherwise elevate blood pressure) and secondly, through increased production of the vasodilator substance, nitric oxide (a beneficial compound that causes relaxation of blood vessels).
- Anthocyanins are another class of polyphenolic anti-oxidants present abundantly in the red grapes. These phyto-chemicals have been found to have an anti-allergic, anti-inflammatory, anti-microbial, as well as anti-cancer activity.
- Catechins, a type of flavonoid tannin group of anti-oxidants, found in the white/green varieties have also shown to possess these health-protective functions.
- Grapes are rich source of micronutrient minerals like copper, iron and manganese. Copper and manganese are an essential co-factor of antioxidant enzyme, superoxide dismutase. Iron is especially concentrated more in raisins. In addition, 100 g of fresh grapes contain about 191 mg of health benefiting electrolyte, potassium.
- They are an also good source of vitamin-C, vitamin A, vitamin K, carotenes, B-complex vitamins such as pyridoxine, riboflavin, and thiamin.
- In addition, the berries are very low in calories. 100 g fresh grapes just provide 69 calories but zero cholesterol levels.