Macrowine 2021
IVES 9 IVES Conference Series 9 From precursor identification to the study of the distribution of 3-methyl-2,4-nonanedione in red wines and spirits

From precursor identification to the study of the distribution of 3-methyl-2,4-nonanedione in red wines and spirits

Abstract

Prematurely aged red wines are marked by intense prune and fig aromatic nuances that dominate the complex bouquet that can be achieved through bottle aging. This oxidation off-flavor is, in part, caused by the presence of 3-methyl-2,4-nonanedione (MND).1 It is interesting to note that similar aromas are also detected in aged spirits. Despite its strong sensory impact in red wines, the precursors of this diketone were not well described.

So, first investigations were performed in order to quantify this compound in young and aged spirits in order to explain these nuances. In addition, determination of MND precursors in red wines as well as the study of oxidation mechanisms on their evolutions will improve our ability to understand its formation pathway in alcoholic beverages.

The first step of this work aimed at identifying a precursor of MND in grapes and wines. Based on the MND distribution in grapes, in young and old wines we hypothesized that ketols might be precursors of this diketone. We describe the chemical synthesis of 2-hydroxy-3-methylnonan-4-one (syn- and anti-ketol) as well as their identification in wines. MND and ketols were quantified by SPME-GC-MS (CI, MeOH) using SIS and MS/MS mode, respectively, in more than 150 Merlot and Cabernet Sauvignon wines from California, Bordeaux, and Switzerland. Oxidation experiments conducted in model wine and red wine demonstrated that ketols are able to produce MND. Based on these data, their role as MND precursor will be discussed. In addition, we also report first results concerning the origin of ketols in grapes and wines.

We also extended our investigations to spirits were old samples can develop similar dried plum aromas. We also report for the first time the distribution of MND in many spirits including Cognac, Armagnac, Brandy, Bourbon, Grappa, Rhum, Whisky. Highest levels were found in grappa (> 10 000 ng/L), exceeding its detection thresholds (100 ng/L). Sensory analysis experiments revealed that this compound contributes to the aroma of spirits. Assay of ketols in these samples revealed that they can be precursors of MND in spirits.

This project has improved our understanding of the formation and evolution of MND in wines, enabling more accurate predictions of the oxidative behavior and aging potential of red wines. In addition, we describe its first identification as well as its sensory impact in spirits

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Alexandre PONS

Université Bordeaux, ISVV, EA 4577, Unité de Recherche Œnologie, F-33882 Villenave d’Ornon, France, Seguin Moreau Cooperage, ZI Merpins, 16103 Cognac, France. Ana PETERSON, Université Bordeaux, ISVV, EA 4577, Unité de Recherche Œnologie, F-33882 Villenave d’Ornon, France. Fannie THIBAUD, Université Bordeaux, ISVV, EA 4577, Unité de Recherche Œnologie, F-33882 Villenave d’Ornon, France. Jean Charles MATHURIN, E. Rémy Martin & C°, Z.I, 16100 Merpins, France. Yannick LANDAIS, Université Bordeaux, ISM, CNRS UMR 5255, Talence, France. Philippe DARRIET, Université Bordeaux, ISVV, EA 4577, Unité de Recherche Œnologie, F-33882 Villenave d’Ornon, France. INRA, ISVV, USC 1366, Unité de Recherche Œnologie, F-33882 Villenave d’Ornon, France

Contact the author

Keywords

aging, red wines, oxidation, aroma, spirits, aroma precursor

Citation

Related articles…

Better understand the soil wet bulb formation with subsurface or aerial drip irrigation in viticulture

The gradual change in rainfall patterns experienced in the south of France vineyards, especially around the Mediterranean sea, means that the vines are increasingly subject to summer drought. The winegrowers developped the use of irrigation techniques to ensure the maintenance of competitive yields in the production of wines under Protected Geographical Indication label. In practice, drip irrigation pipes can be installed above the ground or buried into the soil as well as at different distances from the vine row. The objective of this study was to examine the profiles of the wet bulbs of the soil obtained from two drip irrigation systems : aerial drip located under the vine row and subsurface drip placed in the middle of the inter-row. This experiment took place over two consecutive seasons (2020-2021) on a 3.4 ha Viognier plot in the Mediterranean region (PGI Oc, France) on sandy clay soil. The annual rainfalls were less than 400 mm. Soil water content probes were installed at different depths (20 – 40 – 60 – 80 cm) and at different lateralities from the vine row (30 – 60 – 90 – 120 cm) to control the formation of the soil wet bulb during irrigation. The mapping and the analysis of the data allowed a better understanding and differentiation of the water percolation when irrigating with subsurface or aerial drip. For the same amount of water and without differences of vine water status, it is shown that in a subsurface drip irrigation situation, the size of the wet bulb formed is larger than in aerial drip irrigation system.

Current climate change in the Oplenac wine-growing district (Serbia)

Serbian autochthonous vine varieties Smederevka (for white wines) and Prokupac (for rosé and red wines) are the primary representatives of typical characteristics of wines and terroir of numerous wine-growing areas in Serbia. In the past, these varieties were the leading vine varieties, however, as the result of globalization of winemaking and the trend of consumption of wines from widely prevalent vine varieties, they were replaced by introduced international varieties. Smederevka and Prokupac vine varieties are characterized by later time of grape ripening, and relative sensitivity to low temperatures. Climate conditions can be a restrictive factor for production of high-quality grapes and wine and for the spatial spreading of these varieties in hilly continental wine-growing areas.
This paper focuses on the spatial analysis of changes of main climate parameters, in particular, analysis of viticultural bioclimatic indices that were determined for the purposes of viticulture zoning of wine-growing areas in the period 1961-2010, and those same parameters determined for the current, that is, referential climate period (1988-2017). Results of the research, that is, analysis of climate changes indicate that the majority of examined climate parameters in the Oplenac wine-growing district improved from the perspective of Smederevka and Prokupac vine varieties. These studies of climate conditions indicate that changes of analyzed climate parameters, that is, bioclimatic indices will be favorable for cultivation of varieties with later grape ripening times and those more sensitive to low temperatures, such as the autochthonous vine varieties Smederevka and Prokupac, therefore, it is recommended to producers to more actively plant vineyards with these varieties in the territory of the Oplenac wine-growing district.

Revealing the Barossa zone sub-divisions through sensory and chemical analysis of Shiraz wine

The Barossa zone is arguably one of the most well-recognised wine producing regions in Australia and internationally; known mainly for the production of its distinct Shiraz wines. However, within the broad Barossa geographical delimitation, a variation in terroir can be perceived and is expressed as sensorial and chemical profile differences between wines. This study aimed to explore the sub-division classification across the Barossa region using chemical and sensory measurements. Shiraz grapes from 4 different vintages and different vineyards across the Barossa (2018, n = 69; 2019, n = 72; 2020, n = 79; 2021, n = 64) were harvested and made using a standardised small lot winemaking procedure. The analysis involved a sensory descriptive analysis with a highly trained panel and chemical measurement including basic chemistry (e.g. pH, TA, alcohol content, total SO2), phenolic composition, volatile compounds, metals, proline, and polysaccharides. The datasets were combined and analysed through an unsupervised, clustering analysis. Firstly, each vintage was considered separately to investigate any vintage to vintage variation. The datasets were then combined and analysed as a whole. The number of sub-divisions based on the measurements were identified and characterised with their sensory and chemical profile and some consistencies were seen between the vintages. Preliminary analysis of the sensory results showed that in most vintages, two major groups could be identified characterised with one group showing a fruit-forward profile and another displaying savoury and cooked vegetables characters. The exploration of distinct profiles arising from the Barossa wine producing region will provide producers with valuable information about the regional potential of their wine assisting with tools to increase their target market and reputation. This study will also provide a robust and comprehensive basis to determine the distinctive terroir characteristics which exist within the Barossa wine producing region.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

Analysis of some environmental factors and cultural practices that affect the production and quality of the Manto Negro, Callet and Prensal Blanc varieties

45 non irrigated vineyards distributed in the DO (Denomination) Pla i Llevant de Mallorca and the DO Binissalem Mallorca were used to investigate the characteristics of production and quality and their relationships certain environmental factors and cultural practices. The grape varieties investigated are autochthonous to the island of Mallorca, Manto Negro and Callet as red and Prensal Blanc as white. All plants were measured for four consecutive years in the main production and quality parameters. Among the environmental factors, the type of soil has been studied, more specifically its water retention capacity, the planting density, the age of the vineyard and the level of viral infection. The presence or absence of virus seems to have no effect on any component studied in the varieties studied. For the white variety Prensal Blanc age is negatively correlated with production and the number of bunches, nevertheless it does not cause any effect on the required quality parameters. However, for the red varieties Callet and Manto Negro, the age of the plantation is the variable that best correlates with the quality parameters, therefore the old vines should be the object of preservation by the viticulturists and winemakers in order to guarantee its contribution to the quality of the wines made with these varieties.