Definition of Phenolic Constituents in Red Wine

What are Phenols?

• Phenols are organic compounds found in grape skin and seeds that determine everything from a wine's balance, taste, color, consistency and aroma. Scientifically, they are defined as having a hydroxyl group attached to a carbon atom, according to Britanica.com, and are essentially any organism with an aromatic phenol ring. Phenols are also found in a variety of other foods, including coffee, tea, nuts and fruits, as well as animals and small organisms.

How are They Formed?

• According to CalWineries.com, phenols serve as a defense mechanism for plants. When a plant is fighting off environmental stresses, it is more likely to produce phenols. While most occur naturally, some are also formed during fermentation and aging processes.

Flavonoids

• In red wine, the main type of phenols is called flavonoids, which contribute to as much as 90 percent of a wine's constitution. In white wine, they are nonflavonoids. The major flavonoids in red wine are flavanols, anthocyanins, tannins and catechins.

Types of Flavonoids

• Flavanols and anthocyanins serve as a protecting agent to keep a plant safe from UV ray damage. While anthocyanins contribute to the color and aging of wine, catechins provide the flavor properties in red wines. Additionally, anthocyanins, which are found in stems, can react with tannins, which are found in bark and leaves or in a wood barrel, and have an impact on the aging process of a wine.

Health Benefits

• Phenols are generally heralded for their antioxidant properties. A flood of studies have examined the role of phenols and antioxidants in cardiovascular disease and cancer prevention, with much of it centered on resveratrol, also found in the skin of red grapes. According to the National Cancer Institute, a glass of red wine a day can reduce the risk of leukemia, and breast, skin and prostate cancers. But studies are still unclear exactly why these health benefits are present and whether consuming more than a modicum amount a day has an adverse effect.