One of the most popular among the regularly featuring table fruits, grapes are widely considered as the "queen of fruits" since earlier times. These tiny berries of the Europe and Mediterranean origin are the storehouse of numerous health-promoting phytonutrients such as polyphenolic antioxidants, vitamins, and minerals. No wonder why so many of us often include them in our diet; be it as a fresh table fruits, dry fruits (raisins), juice, or simply in salads!
Botanically, they are small, round berries growing in clusters on a perennial and deciduous woody vine of the genus, Vitis. Today, they widely cultivated under supervised orchards and vineyards all around the world.
|White/green variety||Red/purple variety||Blue/black variety|
In structure, each grape berry features semi-translucent flesh encased inside a smooth, thin skin. Some varieties contain edible seeds, while others are seedless. The color of the berry is because of the presence of polyphenolic pigments in them. Red or purple berries are rich in anthocyanins while white-green berries compose more of tannins, especially, catechin. Interestingly, these antioxidant compounds concentrated densely in the skin and seeds!
The three most important species of grapes grown around the world are; European (Vitis vinifera), North American (Vitis labrusca, and Vitis rotundifolia), and French hybrids.
Some of the 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 the flavorful blue-black cultivars.
Commercially, many cultivars of grapes are grown for different purposes either to be eaten as table fruit, fresh or dried (raisin, currant, sultana) or in wine production.
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.
Resveratrolreduces stroke risk by altering the molecular mechanisms inside the blood vessels. It does so, firstly by reducing the susceptibility of the blood vessel through decreased activity of angiotensin (a systemic hormone causing blood vessel constriction that would otherwise elevate blood pressure) and secondly, through increased production of vasodilator substance, nitric oxide (a beneficial compound that causes relaxation of blood vessels).
Anthocyanins are another class of polyphenolic antioxidants present abundantly in the red grapes. These phytochemicals 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, discovered in the white/green varieties have also shown to possess these health-protective functions.
Grapes are a rich source of micronutrient minerals like copper, iron, and manganese. Copper and manganese are an essential cofactor of the antioxidant enzyme, superoxide dismutase. Iron is especially concentrated in raisins. Besides, 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.
|Principle||Nutrient Value||Percentage of RDA|
|Total Fat||0.16 g||0.5%|
|Dietary Fiber||0.9 g||2%|
|Pantothenic acid||0.050 mg||1%|
|Vitamin A||66 IU||3%|
|Vitamin C||10.8 mg||18%|
|Vitamin E||0.19 mg||1%|
|Vitamin K||14.6 µg||12%|
Fresh grapes can be available all around the seasons. In the stores, choose those that feature plump in consistency, free from surface wrinkles with intact skin, without any cuts or cracks or leaking juice, and firmly attached to a healthy-looking green stem. Lift up the whole bunch in the air and shake gently; loose berries, if any falls off easily.
Buy exactly ripe berries; green grapes should feature slight yellowish hue; red types should be mostly pinkish-red, while purple and blue-black types should be profound and rich in color.
Since grapes tend to spoil early and ferment at room temperature, they should always be stored in the refrigerator. Loosely wrap washed berries in a paper towel and place them in a zip pouch bag set at high relative humidity. This way, they will keep fresh in the refrigerator for few days.
|Grape juice is a delicious juice drink.
Photo: Mai Le
Just before eating, wash the whole bunch to remove any pesticide residues and dirt by rinsing in cold-water for a couple of minutes. Place then in fresh cold water and gently swish them around few times. Pat dry using a soft cloth.
If you are not going to consume the whole bunch at one go, then separate it into small clusters using scissors. This way, you can keep the remaining berries fresher by preventing their stem from drying out.
Although its seeds are rich in nutrients, seedless grapes make the recipes much more pleasant to eat.
Here are some serving tips;
Enjoy them as they are, without any seasonings/additions.
Dry grapes (raisin, currant, and sultana) are being used in confectionary, puddings, cakes, muffins, bread, etc.
The food industry can also use them for the preparation of jams, jellies, juice and wine.
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Further reading and Resources:
Refer Stanford School of MedicineCancer information Page- Nutrition to Reduce Cancer Risk. (Opens in new window).