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IVES 9 IVES Conference Series 9 VOLATILE AND GLYCOSYLATED MARKERS OF SMOKE IMPACT: LEVELS AND PATTERNS OBSERVED IN 2020 WINES FROM THE UNITED STATES WEST COAST

VOLATILE AND GLYCOSYLATED MARKERS OF SMOKE IMPACT: LEVELS AND PATTERNS OBSERVED IN 2020 WINES FROM THE UNITED STATES WEST COAST

Abstract

Smoke impact in wines is caused by a wide range of volatile phenols found in wildfire smoke. These compounds are absorbed and accumulate in berries, where they may also become glycosylated. Both volatile and glycosylated forms eventually end up in wine where they can cause off-flavors, described as “smoky”, “bacon”, “campfire” and “ashtray”, often long-lasting and lingering on the palate. In cases of large wildfire events, economic losses for all wine industry actors can be devastating.

In order to assess smoke impact, a selection of volatile and glycosylated smoke-derived phenols is pro-posed, mainly based on research from Australia (1, 2). It includes the volatile phenols guaiacol, 4-methyl-guaiacol, ortho-, meta- and para- cresol, phenol, syringol, and 4-methylsyringol, as well as their glycosylated forms guaiacol rutinoside, 4-methylguaiacol rutinoside, cresol rutinoside, phenol rutinoside, syringol gentiobioside, and 4-methylsyringol gentiobioside. The accurate and reproducible measurement of these markers is now possible worldwide, due to the commercial availability of standards and isotopic analogues.

The 2020 vintage has been particularly affected by wildfires all over the western part of the United States, giving us an opportunity to collect extensive data for this suite of markers in wines from smoke-exposed grapes.

In the large majority of cases, levels of both volatile and glycosylated markers in wines appeared closely related to the intensity of vineyard’s exposure to smoke. This confirmed the relevance of these markers in the western United States.

In some cases, however, volatile markers were relatively low, sometimes barely indicating any exposure to smoke, while glycosylated markers were high. This suggested very efficient glycosylation mechanisms in grapes and vines exposed to smoke.

We also observed opposite patterns, meaning high levels of volatile markers in combination with low levels of glycosylated markers. This may be the consequence of impaired glycosylation pathways in the plants, possibly related to a severe heat wave experienced in mid-August 2020.

These observations confirm that measuring both volatile and glycosylated markers is advisable in order to identify wines from smoke exposed grapes.

 

1. Hayasaka, Y., Parker, M., Baldock, G.A., Pardon, K.H., Black, C.A., Jeffery, D.W. and Herderich, M.J. (2013) Assessing the impact of smoke exposure in grapes: development and validation of a HPLC-MS/MS method for the quantitative analysis of smoke derived phenolic glycosides in grapes and wine. Journal of Agricultural and Food Chemistry 61, 25–33.
2. Krstic, M.P., Johnson, D.L. and Herderich, M.J. (2015) Review of smoke taint in wine: smoke-derived volatile phenols and their glycosidic metabolites in grapes and vines as biomarkers for smoke exposure and their role in the sensory perception of smoke taint. Australian Journal of Grape and Wine Research 21, 537–553.

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Eric Hervé¹, Darren Gullick¹ , Azeem Hasan¹, Anindya Pradhan¹, Gordon Burns¹

smoke impact, volatile phenols, glycosylated phenols, wine

Contact the author*

Keywords

smoke impact, volatile phenols, glycosylated phenols, wine

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

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