Polyphenolic compounds in Sauvignon Blanc - from grapes to wine

At harvest, the metabolic composition of wine grapes reflects the accumulated effect of the environmental conditions, the stresses endured, and viticultural manipulations applied during the growing season. The role of the winemaker is to extract and nurture this “metabolite potential” throughout th...

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Main Authors: Davin Williams, Anscha Zietsman, Jeanne Brand, Hans Eyeghe-Bickong, Melané Vivier
Format: Article
Language:English
Published: International Viticulture and Enology Society 2025-01-01
Series:OENO One
Subjects:
Online Access:https://oeno-one.eu/article/view/8298
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author Davin Williams
Anscha Zietsman
Jeanne Brand
Hans Eyeghe-Bickong
Melané Vivier
author_facet Davin Williams
Anscha Zietsman
Jeanne Brand
Hans Eyeghe-Bickong
Melané Vivier
author_sort Davin Williams
collection DOAJ
description At harvest, the metabolic composition of wine grapes reflects the accumulated effect of the environmental conditions, the stresses endured, and viticultural manipulations applied during the growing season. The role of the winemaker is to extract and nurture this “metabolite potential” throughout the winemaking process. However, it is typically difficult to relate this grape potential to that of the eventual wines.  In this study, a holistic view of Sauvignon Blanc grape and wine polyphenolic compounds was attempted by measuring these compounds from different matrices, from ripe grape tissues up to the final wine, including the submatrices, such as juice, pomace and sediment. Sauvignon Blanc vines from one vineyard block were manipulated to yield berries with distinctly different phenolic potentials by creating a high light (HL) or a low light (LL) microclimate in the fruiting zone of the canopy during the growing season. The analyses of the HL and LL berries and wines, as well as concomitant analyses of the phenolic compounds in the submatrices, allowed their tracing as they were (i) transferred from one matrix to another, (ii) lost as waste products, or (iii) affected by different winemaking practices (skin contact and/or fermentation in contact with the juice sediment) implemented in the experimental design. In berries, flavonols showed the largest increase due to sun exposure (HL treatment) but were absent from the juice samples at all juice processing stages. They were however detected in the juice sediment, together with high concentrations of organic acids and sugars. Juice processing was noted for dramatic fluctuations in metabolite concentrations suggesting intense metabolic activity in this pre-fermentation matrix. Both skin contact and sediment contact treatments delivered wines with higher concentrations of coutaric acid (the ester formed from coumaric and tartaric acid) and the flavanol catechin while epicatechin concentrations was unaffected.  The higher catechin concentrations did not lead to increased perceived bitterness in the wines, except in the sediment contact treatments. The total phenolic compound concentration of wine from LL (low phenolic potential) grapes was comparable to wine from HL (high phenolic potential) grapes, when skin contact, or sediment contact treatments were employed. From a sensory perspective, the sediment contact decreased the fruity aromas of Sauvignon Blanc, while the skin contact treatment enhanced the sensorial properties of the wines made from the LL grapes, allowing increased extraction from the skin-accumulated impact compounds.
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spelling doaj-art-1f24e4039a9e4445bbd86510cf1b9e5c2025-01-19T11:10:17ZengInternational Viticulture and Enology SocietyOENO One2494-12712025-01-0159110.20870/oeno-one.2025.59.1.8298Polyphenolic compounds in Sauvignon Blanc - from grapes to wineDavin Williams0Anscha Zietsman1Jeanne Brand2Hans Eyeghe-Bickong3Melané Vivier4South African Grape and Wine Research Institute, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.South African Grape and Wine Research Institute, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.South African Grape and Wine Research Institute, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.South African Grape and Wine Research Institute, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.South African Grape and Wine Research Institute, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa. At harvest, the metabolic composition of wine grapes reflects the accumulated effect of the environmental conditions, the stresses endured, and viticultural manipulations applied during the growing season. The role of the winemaker is to extract and nurture this “metabolite potential” throughout the winemaking process. However, it is typically difficult to relate this grape potential to that of the eventual wines.  In this study, a holistic view of Sauvignon Blanc grape and wine polyphenolic compounds was attempted by measuring these compounds from different matrices, from ripe grape tissues up to the final wine, including the submatrices, such as juice, pomace and sediment. Sauvignon Blanc vines from one vineyard block were manipulated to yield berries with distinctly different phenolic potentials by creating a high light (HL) or a low light (LL) microclimate in the fruiting zone of the canopy during the growing season. The analyses of the HL and LL berries and wines, as well as concomitant analyses of the phenolic compounds in the submatrices, allowed their tracing as they were (i) transferred from one matrix to another, (ii) lost as waste products, or (iii) affected by different winemaking practices (skin contact and/or fermentation in contact with the juice sediment) implemented in the experimental design. In berries, flavonols showed the largest increase due to sun exposure (HL treatment) but were absent from the juice samples at all juice processing stages. They were however detected in the juice sediment, together with high concentrations of organic acids and sugars. Juice processing was noted for dramatic fluctuations in metabolite concentrations suggesting intense metabolic activity in this pre-fermentation matrix. Both skin contact and sediment contact treatments delivered wines with higher concentrations of coutaric acid (the ester formed from coumaric and tartaric acid) and the flavanol catechin while epicatechin concentrations was unaffected.  The higher catechin concentrations did not lead to increased perceived bitterness in the wines, except in the sediment contact treatments. The total phenolic compound concentration of wine from LL (low phenolic potential) grapes was comparable to wine from HL (high phenolic potential) grapes, when skin contact, or sediment contact treatments were employed. From a sensory perspective, the sediment contact decreased the fruity aromas of Sauvignon Blanc, while the skin contact treatment enhanced the sensorial properties of the wines made from the LL grapes, allowing increased extraction from the skin-accumulated impact compounds. https://oeno-one.eu/article/view/8298Polyphenolic compoundshigh light exposuregrape-to-wine analysisjuice processingSauvignon blanc
spellingShingle Davin Williams
Anscha Zietsman
Jeanne Brand
Hans Eyeghe-Bickong
Melané Vivier
Polyphenolic compounds in Sauvignon Blanc - from grapes to wine
OENO One
Polyphenolic compounds
high light exposure
grape-to-wine analysis
juice processing
Sauvignon blanc
title Polyphenolic compounds in Sauvignon Blanc - from grapes to wine
title_full Polyphenolic compounds in Sauvignon Blanc - from grapes to wine
title_fullStr Polyphenolic compounds in Sauvignon Blanc - from grapes to wine
title_full_unstemmed Polyphenolic compounds in Sauvignon Blanc - from grapes to wine
title_short Polyphenolic compounds in Sauvignon Blanc - from grapes to wine
title_sort polyphenolic compounds in sauvignon blanc from grapes to wine
topic Polyphenolic compounds
high light exposure
grape-to-wine analysis
juice processing
Sauvignon blanc
url https://oeno-one.eu/article/view/8298
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