Establishing advanced chromatographic tannin analysis techniques for assessing the influence of different winemaking procedures on red wine tannins

Project Number
WW WDT 15-02

Project title
Establishing advanced chromatographic tannin analysis techniques for assessing the influence of different winemaking procedures on red wine tannins

Project leader
Du Toit, W J

Institution
University of Stellenbosch. Faculty of Science. Department of Chemistry and Polymer Sciences

Team members
Du Toit, W J
De Villiers, A
Buica, A
Venter, P
Banvelos, G

Project description
Tannins play a critical role in the colour stabilization, fullness and mouth feel of red wines. Grape derived tannins form complex pigments with anthocyanins during winemaking, which affects the colour and taste of red wine. Certain aspects of wine tannin research, such as the effect different red grape clones of the same cultivar have on tannin levels and conformation, have not been investigated. It is known that tannin concentrations and structures change during winemaking, but how tannin conformation changes during ripening, fermentation and ageing, and what effects this might have on the sensory characteristics of red wines, are not known. Literature reports indicate preferred tannin-to-anthocyanin ratios for successful red wine maturation, and this must be scientifically investigated.

Despite the vital role tannins play in determining many important wine characteristics, comparatively little is currently know about the exact chemical composition of this diverse group of compounds. This may be ascribed to the complexity of wine tannins, and is exacerbated by the alteration in tannin chemical composition during wine ageing. The knowledge of the chemical composition of the wine tannins in general can primarily be ascribed to the lack of sufficient analytical techniques for detailed characterization.

This project aims to develop and apply novel and analytical methodologies to investigate the chemical composition of red wine tannins. For this purpose, 1-dimensional HPLC-FL-DAD suitable for the routine analysis of grape and wine tannins will be developed. Furthermore, comprehensive 2-dimensional liquid chromatography (LC×LC) will be developed and applied to the detailed chemical characterization of tannin fractions, while advanced mass spectrometric (MS) techniques will be employed for structural elucidation purposes

Presentation(s)
Terblanche, E. 2016. Development of hydrophilic interaction chromatography(HILIC) and reversed phase LC (RP-LC) methods hyphenated to UV, fluorescence and high-resolution mass spectrometry for the accurate quantification of grape and wine tannins. Paper presented at the 38th South African Society of Enology and Viticulture Conference. 23-25 August, Somerset West, South Africa.

Terblanche, E. 2016. Development of hydrophilic interaction chromatography(HILIC) and reversed phase LC (RP-LC) methods hyphenated to UV, fluorescence and high-resolution mass spectrometry for the accurate quantification of grape and wine tannins. Paper presented at the ChromSAAMS 2016 Conference. 11-14 September, Vanderbijlpark, South Africa.

Garrido-Bañuelos, G, Buica, A, Moore, J P and Du Toit, W J. 2016.Understanding the relationship between phenolic extractability during fermentation and compositional changes of the grape skins cell walls of Vitis vinifera L. Shiraz grapes harvested at different ripening stages. Paper presented at the 38th South African Society of Enology and Viticulture Conference. 23-25 August, Somerset West, South Africa.

Garrido-Bañuelos, G, Buica, A and Du Toit, W J. 2016. Chemical and sensory evaluation over time of Vitis vinifera L. Shiraz wines made from four different ripening stages. Paper presented at the 38th South African Society of Enology and Viticulture Conference. 23-25 August, Somerset West, South Africa.

 

 

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