LAUSR

BACKGROUND As a wine ages, altered sensory properties lead to changes in perceived quality and value. Concurrent modification of anthocyanin and tannin occur forming pigmented tannin, softening astringency and retaining persistent color. Wine tannin extracts of 1990 and 2010 vintages of Oakville Station Cabernet Sauvignon have been analyzed using normal phase chromatography with tandem quadrupole time of flight mass spectroscopy (QToF) to investigate the compositional differences in their pigmented tannin fractions. RESULTS The older wine demonstrates much greater structural diversity and a range of more polar compounds, while the younger wine contains fewer observed ion peaks. Several hundred molecular features are observable, and, as expected, there is progression to higher molecular weights after long aging. Between 7 and 16% of molecular features could be matched to a database of anticipated pigmented tannin compounds. Many signals had multiple possible isomeric identities, but fragmentation to resolve their identity was stymied by low sensitivity of MS2 capability provided by QToF, so isomeric disambiguation is incomplete. CONCLUSION The chromatography displayed a high degree of resolution in aged wines, separating many of the known pigment types, including aldehyde bridged compounds, pyranoanthocyanins, and direct condensation products among others, as well as resolving a great number of unknown compounds. Expanding our understanding of red wine pigments will lead to better wines as winemakers will be able to associate quality with particular wine pigment profiles once we can distinguish the relevant patterns in those pigments. This article is protected by copyright. All rights reserved.