Role in bitterness and astringency

Phenolic compounds play a vital role in the flavor of red wines. They are responsible for some positive tasting characteristics, but also for some rather unpleasant, negative aspects. Body, backbone, structure, fullness and roundness are all organoleptic qualities characteristic of great red wines. On the other hand, bitterness, roughness, harshness, astringency and thinness are faults that must be avoided as they are incompatible with quality. 

It is a fact that phenolic compounds, namely flavonoids, play a crucial role in wines as they are responsible for the color of red and white wines and contribute to their mouth characteristics (astringency and bitterness). In Vitis vinifera grapes and wines, this group of compounds is structurally diversified and comprises different classes of compounds, such as anthocyanins, flavan-3-ols (catechins and condensed tannins), flavonols, flavones, and dihydroflavonols. 

Phenolic acids contribute to the sensory and nutritional qualities of fruits, vegetables, and derived foods. Directly or indirectly, they play a role in color, astringency, bitterness, and aroma, and they also are of great interest to humans, because of their antioxidant capacity [2,4]. 

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