When people eat grapes, they often eat the skin only with seedless white grapes, while spitting out the skin when eating other grapes because the grape skin has a bitter taste. However, from a nutritional perspective, you should not spit out the grape skin when eating grapes.
The skin of grapes is rich in a polyhydroxy phenolic compound—resveratrol, which has effects such as lowering blood lipids, preventing thrombosis, preventing arteriosclerosis, and enhancing immune function.
Another important substance in grape skin—tannin, has the effects of anti-allergy, anti-aging, enhancing immunity, and preventing cardiovascular and cerebrovascular diseases.
The anthocyanins contained in grape skin have strong antioxidant, anti-mutagenic, liver function reduction, and cardiovascular protection functions.
Grape skin also has anti-cancer effects. Researchers at the University of Illinois College of Pharmacy in the United States have found that this substance exists in more than 70 plants such as peanuts and grapes, with the highest amounts in grape skins and red wine.
Because most of the grapes currently on the market have pesticide residue problems, it is essential to wash them thoroughly before eating them with the skin. It is best to rinse with water first, combined with a detergent that can effectively remove pesticide ingredients, and wash for more than two minutes. However, soaking in plain water or salt water is not advisable because soaking in water can easily promote the penetration of residual pesticides on the grape surface into the pulp.