Characterization of Bitter and Astringent Proanthocyanidins during Winemaking
Polyphenols, including proanthocyanidins (i.e., tannins), are widely distributed in foods and
beverages, including grapes and wines and they are key constituents impacting bitter and
astringent perception. Due, at least in part, to their chemical complexity, the changes in
proanthocyanidin concentration and chemical structure that occur during winemaking and that
impact sensory properties have not been fully evaluated.
We have completed development and validation of an ultra-high performance liquid
chromatography quadrupole time-of-flight mass spectrometry (UHPLC-qTOF MS) approach to
characterize the subunit composition and molecular weight/average degree of polymerization of
wine proanthocyanidins. Wines with different maceration treatments were analyzed and we were
able to demonstrate differences in proanthocyanidin composition as a function of maceration
treatment. This work provides important insight into the impact of maceration treatments on
proanthocyanidin composition of wines.