IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Botrytis cinerea: Coconut or Catastrophe? Quantification of γ-Nonalactone in Botrytised and Non-Botrytised New Zealand Wines

Botrytis cinerea: Coconut or Catastrophe? Quantification of γ-Nonalactone in Botrytised and Non-Botrytised New Zealand Wines

Abstract

g-Nonalactone has been identified as a significant contributor to the aroma profile of a range of wines and is associated with stonefruit and coconut descriptors. The exact route of g-nonalactone biosynthesis in wine has not been fully elucidated; however, precursors including 4-oxononanoic acid, linoleic acid, 13-hydroxyoctadeca-9,11-dienoic acid (13-HODE) and 9-hydroxyoctadeca-10,12-dienoic acid (9-HODE) have been identified in incubation experiments. Wines produced from grapes infected with “noble rot” caused by Botrytis cinerea fungus generally show higher concentrations of g-nonalactone compared to non-botrytised white wines, but the relative contribution of potential formation pathways has not been elucidated. To assess the effect of linoleic acid on the production of g-nonalactone in wine, fermentations with and without added linoleic acid were carried out in synthetic grape must (SGM) at 28 °C using commercial Saccharomyces cerevisiae EC1118. Prior to g-nonalactone quantitation in the finished wines and in a subset of six Australian and New Zealand commercial wines, several routes for the synthesis of a deuterated analogue of g-nonalactone were attempted, before the deuterated d6-analogue of g-nonalactone from its non-deuterated analogue was produced successfully. Subsequently, attempts were made to utilise the d6-analogue as an internal standard for the measurement of g-nonalactone using gas chromatography-mass spectrometry. However, the synthetic deuterated g-nonalactone analogue proved to be an inappropriate internal standard for this purpose, due to incomplete incorporation of deuterium atoms. 2-Octanol was instead used as a surrogate internal standard. g-Nonalactone was successfully identified (above the limit of detection, 4.12g/L) in two commercial New Zealand botrytised wine samples, and one fermentation sample to which linoleic acid (132 mg/L) had been added. This suggests a possible link between the effect of Botrytis cinerea and/or linoleic acid, and increased levels of g-nonalactone in wine. The promising results in these preliminary experiments have led to an improved internal standard being sought out for the quantification of g-nonalactone in wine, and further investigation of its biosynthesis. A 13C4-labelled g-nonalactone analogue was successfully synthesized based on a previous method, with four 13C atoms being introduced into the molecule via two Wittig olefination steps. This standard will be used for a much larger survey of approximately 40 botrytised and non-botrytised New Zealand wines, in addition to further fermentation experiments assessing the effects of the addition of a wider range of putative precursors.

DOI:

Publication date: June 24, 2022

Issue: IVAS 2022

Type: Poster

Authors

Miller Gillean1, Fedrizzi Bruno1, Barker David1, Pilkington Lisa1 and Deed Rebecca1

1The University of Auckland, School of Chemical Sciences

Contact the author

Keywords

Lactones, Botrytis, White wine, New Zealand, GC-MS

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Building of a hierarchy of wines based on terroirs: an initiative from the producers of Muscadet

The Muscadet area is situated in the southeast of Nantes, close to the Atlantic coast. It constitutes the western extension
of the French vineyard “Loire Valley”. The Muscadet is renowned and often spontaneously linked to a white wine.
However it remains misconceived as an ordinary wine, lacking authenticity.

How the physical components of the terroir can differently intervene in French wines DPO definitions.Example of Côte de Nuits in Burgundy

European regulations describe what elements must be given in the specifications of DPO determination ; mainly production conditions, links between quality and products characteristics and the physical traits of the production area. These elements are given in the “link to terroir” paragraph relating natural and human factors, detailed product characteristics linked to the geographical area and at last interactions between product originality and the geographical area.

Vignobles sur les pentes en Bourgogne : l’aube d’un nouveau modèle de l’Antiquité au Moyen Âge

La découverte d’une vigne gallo-romaine en plaine à Gevrey-Chambertin (Côte-d’Or) constitue un point important pour la compréhension de la construction des terroirs viticoles de Bourgogne. Sa situation en plaine constitue pour nous le point de départ d’une large réflexion sur la mise en place du modèle de viticulture de coteau qui prévaut en Bourgogne et sur les facteurs de ce changement de norme de qualité viticole. Les sources mobilisées pour cette approche interdisciplinaire et diachronique sont géomorphologiques, archéologiques et textuelles.

Everything else, it’s work ”Socio-cultural dimensions of terroir among Bordeaux winemakers

In 2010, the OIV adopted a resolution that defines ‘terroir’. The OIV definition understands terroir as the result of the interactions between the physical specificities of a space and human labor, with an emphasis on the subsequently produced collective knowledge (OIV-VITI 333-2010); by doing so, it alludes to the social and cultural dimensions of terroir.

Swiss program for the creation of fungal disease resistant grape varieties in Switzerland

Grapevine breeding is part of the research program of Agroscope in Switzerland since 1965. From 1965 to 1995, the aim of the Vitis vinifera crosses was to obtain a high resistance to grey rot (Botrytis cinerea), one of the most virulent fungal pathogens in the Swiss vineyard. In 2021, the grape varieties released from this first breeding program covered 936 ha of the 15’000 ha of the Swiss vineyard.
In 1996, a second breeding program aimed at obtaining, by classical interspecific hybridization, grape varieties resistant to downy mildew (Plasmopara viticola) and powdery mildew (Erisyphe necator) and less sensitive to grey rot (Botrytis cinerea). In order to accelerate and make the selection process more reliable, an early biochemical test was developed based on the natural defense mechanisms of the vine against downy mildew (stilbene phytoalexins). The synthesis of stilbenes (i.e., resveratrol and its oxidized dimers - and -viniférine) and pterostilbenes (methylated derivative) is among the most efficient induced defense mechanisms of grapevine against fungal pathogens on both the leaves and the clusters.