Identification of the major drivers of 'phenolic' taste in ... - GWRDC

AWRI: Identification Of The Major Drivers Of ‘Phenolic’ Taste In White Wines
8.5.3 Phenolic Measures (HPLC) – 2010 wines
Over 50 phenolic compounds were detected, putatively identified and quantified in this study and they
can be classified in several ways: in a broad, polyphenolic class (hydroxybenzoic acids, hydroxycinnamic
acids, flavan-3-ols, flavonols, GRP-conjugates etc.), or with these subdivided into ethyl esters (EE) or
glycoconjugates. A list of the identified compounds, their classifications groups and the equivalent units
used for quantification is given in Appendix B, Table B-7. These data are presented alongside average
literature values collected by the INRA Montpellier as part of the Phenols Explorer project (Neveu et al.
2010). The total phenolics were determined by summing unidentified early eluting compounds (expressed
as mg/L GAE) and all the named compounds. Mean values are shown for each variety in Figure 8-9 and
sorted by treatment of all three varieties in Figure 8-10.
The concentrations of the broad polyphenolic classes averaged across all varieties and treatments are
given in Figure 8-11, by variety (Figure 8-12), and by winemaking treatment (Figure 8-13). Some classes
such as the flavonols, flavanones, phenols, and cinnamic acids and GRP conjugates vary widely between
varieties. Riesling tends to show higher cinnamic acids, flavanones and flavanol-type compounds, while
Viognier has higher GRP analogues and flavonols (Figure 8-12). The wines from macerated juices had
the highest concentrations in flavonols, flavanonols and cinnamic acids (Figure 8-13) and would suggest
that these compounds are located in skins and increase in concentrations during cold soaking. However,
benzoic acids, other phenols and flavan-3-ols show fairly constant concentrations across the different
treatments and potentially coming only from grape flesh are not influenced by maceration.Figure 8-14
shows a finer sub-division of some of the broad classes into ethyl esters (EE) and glycoconjugates
averaged across all varieties and treatments. The variations described earlier can be more precisely
ascribed to free hydroxycinnamoyl tartaric acids (caftaric acid, coutaric acid and fertaric acid) and
flavonol glycoconjugates (mainly quercetin-3-O-glucuronide).
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