Macrowine 2021
IVES 9 IVES Conference Series 9 First identification of a glycosylated fraction involved in mushroom-off-flavor in grapes: influence of B. cinerea, powdery mildew and C. subabruptus

First identification of a glycosylated fraction involved in mushroom-off-flavor in grapes: influence of B. cinerea, powdery mildew and C. subabruptus

Abstract

An organoleptic defect, called fresh mushrooms off-flavor, appeared in wines and spirits since the 2000’s. Numerous researches demonstrated that octen-3-one, octan-3-ol and octen-3-ol (C8 compounds) were involved in the mushroom off-flavor in wines (Pallotta et al., 1998), (Darriet et al., 2002). Botrytis cinerea and other moldsplayed a role in the metabolism of such molecules directly on the grapes (La Guerche et al., 2006). Moreover, producers couldn’t detect this off-flavor in must but it appeared only in finished wines and the intensity can vary considerably during ageing of wines. Several biogenesis pathways have been proposed to explain the mushroom off-flavor in foods. In the fungus kingdom, the formation of C8 molecules came from the transformation of linoleic acid under the action of several enzymes (Wurzenberger & Grosch, 1984). Glycosidic precursors of octen-3-ol have been identified in several plants such as recently in soybean (Matsui et al., 2018). However, under oenological conditions, no clear mechanism has been established yet. AIM: So, the aim of this work was to (i) identify glycosidic precursors of C8 compounds and (ii) to evaluate the influence of different rots on the glycosylated fractions of different grape varieties. For this purpose, we studied different grades of rot defined by visual intensity (healthy, 1-5%, 10-15% and 20-25% of rots) of grapes and musts of Meunier, Pinot noir and Chardonnay affected by Botrytis cinerea, Powdery mildew and Crustomyces subabruptus. METHODS: From analytical point of view, glycosylated precursors were extracted on C18 cartridges (Lichlorut RP-18, 500 mg),then cleaved by a beta-glycosidase enzyme (Rapidase Revelation Aroma, 40°C, Overnight) and aglycones were analyzed byGC-MS (FS and SIM mode) as reported by Schneider in 2001. RESULTS: For the first time, we identified a glycosylated fraction able to release fresh mushroom aroma (octen-3-one, octen-3-ol, octan-3-ol) in Meunier and Pinot noir musts. Indeed, contaminated musts of Pinot noir treated by beta glucosidase enzyme released three times more octen-3-one than control. In the samples infected with Powdery mildew, we didn’t observe any production of these glycosides. Botrytis cinerea seemed to decrease the level of octen-3-one glycoside(s) as soon as level contamination reached at least 1%. Finally, a Pinot noir must contaminated by Crustomyces subabruptus involved an increase of the glycosylated fraction responsible for the octen-3-one by 31% in comparison with uncontaminated sample. CONCLUSION: In conclusion, the identification of a glycosylated fraction able to release fresh mushroom aroma compounds opens avenue to better understand the source of this specific taint and constitutes the first step to help winemakers to avoid off-flavor.

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Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Léa Delcros 

MHCS, Comité Champagne, Epernay, France,Teddy GODDET, SPO, Univ Montpellier INRAE, Institut agro, Montpellier, France  Sylvie COLLAS, Comité Champagne, Epernay, France  Marion HERVE, MHCS, Epernay, France  Bruno BLONDIN, SPO, Univ Montpellier INRAE, Institut agro, Montpellier, France  Aurélie ROLAND, SPO, Univ Montpellier, INRAE, Institut agro, Montpellier, France

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octen-3-one, octen-3-ol, glycosides, mushroom off-flavor, wine, botrytis cinerea, powdery mildew, crustomyces subabruptus

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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.

Upscaling the integrated terroir zoning through digital soil mapping: a case study in the Designation of Origin Campo de Borja

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Phenolic composition of Tempranillo Blanco grapes changes after foliar application of urea

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Sustaining wine identity through intra-varietal diversification

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Macrowine 2021
IVES 9 IVES Conference Series 9 First identification of a glycosylated fraction involved in mushroom-off-flavor in grapes: influence of B. cinerea, powdery mildew and C. subabruptus

First identification of a glycosylated fraction involved in mushroom-off-flavor in grapes: influence of B. cinerea, powdery mildew and C. subabruptus

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

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