Molar mass 312.229 g/mol | Boiling point 618.2 °C | |
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Caftaric acid is a non-flavanoid phenolic compound.
It is found in grapes (Vitis vinifera) and impacts the color of white wine. Many believe this molecule is responsible for the yellowish-gold color seen in some whites wines. Aside from wine, it is abundantly present in raisins. It also occurs in Cichorium intybus (common chicory) and is one of the bioactive components of Echinacea purpurea (Eastern purple coneflower).
Caftaric acid and caffeic acid are in a class of chemicals known as cinnamates (hydroxycinnamic acids). Caftaric acid is formed when caffeic acid and tartaric acid undergo esterification. But, during fermentation, caftaric acid is oxidized into its principal components.
Caftaric acid has a good bioavailability when fed in rats. Intact trans-caftaric acid was detected in rat plasma along with its O-methylated derivative trans-fertaric acid.
In wine
Winemakers measure caftaric acid levels as their primary method to estimate the oxidation levels that a wine has undergone. For example, press wines, which undergo a high degree of oxidation, will have little to no caftaric acid.
Grape reaction product (2-S glutathionyl caftaric acid) is an oxidation compound produced from caftaric acid and found in wine. Malvidin 3-glucoside alone is not oxidized in the presence of grape polyphenol oxidase (PPO), whereas it is degraded in the presence of a crude grape PPO extract and of caftaric acid, forming anthocyanidin-caftaric acid adducts.