Definition - What does Antioxidant mean?
An antioxidant is a substance which prevents the process of oxidation. They are used often in the manufacture of foods, beverages and wine to prevent any spoilage due to oxygen exposure. Common antioxidants used in wine are vitamin C, vitamin E and sulphur dioxide.
Specifically, in winemaking, examples of antioxidants used throughout the process are sulfates, nitrogen and argon.
WineFrog explains Antioxidant
An antioxidant has the ability to preserve a wine (or any other beverage and/or food) to prevent or prolong it from spoiling.
The wine grape itself contains many natural antioxidants. One of the most recognized antioxidants is Resveratrol. This is an antioxidant naturally found in grapes, with more concentrations in red wine grapes, and other natural foods (peanuts, some berries and chocolate). Its main function is to preserve the fruit on the grapevine during periods of the growing season when the vine is stressed.
Other naturally occurring antioxidants in grapes are citric acid and tannin (tannic acid).