Flavonoids Found in Grapes

A few days ago, I blogged about the Nonflavonoid Phenols in Grapes. Today, I'm reviewing the flavonoid phenols that are found in grapes. My plan is to review the phenolic compounds that come from:

• the grapes
• the yeast
• either fermentation or storage in oak barrels

This review is to help me understand a little of the chemistry and the origin of the flavors and color in wine based on the phenolic content.
In my previous blog on the nonflavonoid phenols, the hydroxycinnamic acids and their corresponding cinnamates had in common, the "phenol" chemical moiety shown below on the left. The flavonoids also called diphenylpropanoids will have in common the chemical moiety shown below on the right.¹

The flavonoid structure can be modified to yield flavan-3-ols, flavonols, and anthocyanins. These compounds all come from the grape.

In my next blog, I'll elaborate on the compounds found in grapes that are members of the flavan-3-ol family. Helpful hint: You can see a larger version of the structure by clicking on the image.
References:
1. Douglas Adams, VI257, Lesson 8, pg. 21.
All structures were drawn by the freely available drawing program from ACD Labs called ACD/ChemSketch Freeware.