Project title
Provenance determination of South African wines

Project leader
Coetzee, P

Institution
ARC Infruitec-Nietvoorbij Rand Afrikaans University

Project description
A lack of knowledge exists on the phenol composition of local red grapes and wine and on the impact these colour and taste compounds have on wine quality. This knowledge is essential in the optimisation of viticultural and oenological techniques to produce optimal quality wines.

One of the main goals of this project, i.e. to determine the phenol composition of a spectrum of red grapes and wines, has already been realized in part by the analyses of Pinotage, Shiraz and Cabernet Sauvignon wines from the 2002 season. Wines were sampled from the Young Wine and Veritas Wine shows according to cultivation distribution in wine producing areas. A liquid chromatographic technique, that is able to determine 38 individual phenols per wine, has been implemented for the analysis of these wines.

Interesting cultivar differences have been noted in the levels of certain phenols. The levels of caffeic acid and its tartaric acid derivative, caftaric acid, are significantly higher in Pinotage compared to Shiraz and Cabernet Sauvignon. Notably higher levels of total analysed flavonols were observed in Shiraz compared to the other two cultivars. These findings agree with those from the 2001 season, but need to be verified further by the analysis of more wines and also grapes over a number of seasons to determine possible seasonal effects.

Cultivar differences in phenol composition can be used in identifying colour and taste impact phenolic compounds. Identification of such compounds will be an important tool in realizing another main goal of this project, i.e. to apply the knowledge obtained from the phenol composition determination in optimising viticultural and oenological techniques to produce wines of high quality. In so doing technology will be developed which can improve South Africa's competitiveness on the international markets.

This is true especially seen in the light that the local wine production pattern is turning from white to red wine. The ratios of the main anthocyanins relative to one another in wines are increasingly being used as a measure of wine authenticity. These ratios were determined for the analysed wines from the 2002 season. The data indicate slight distinctions between Pinotage, Shiraz, and Cabernet Sauvignon wines based on these ratios. These data could be of value in setting a standard of characteristic anthocyanin ratios in South African wines

Presentation(s)
1. Van der Linde, G. Fischer and Coetzee, P P. 2005. Correlation of the trace element fingerprint of grapes, grape juice and the final wine.
Colloquium Spectroscopium Internationale XXXIV,4-9 September. University of Antwerpen, Antwerpen, Belgium.
2. Coetzee, P P. 2005. Fingerprinting of South African wines using ICP-MS multi-element data and multivariate statistics. Symposium and Workshop NRF-Flandres Colaboration, het Pand, 10 September, Ghent University, Ghent, Belgium.
3. Coetzee, P P. 2005. ııB/ışB ratio measurements by ICP-MS for wine authentication. Symposium and Workshop NRF-Flanders Collaboration, Het Pand, 10 September, Ghent University, Ghent, Belgium.
4.  Coetzee, P P. 2006. Multi-element analysis and boron isotope ratio measurements in South African wines by ICP-mass spectrometry and their classification according to geographical origin. 29th Conference of the South African Society for Enology and Viticulture, 15-17 November, Somerset West, South Africa.
5.  Coetzee, P P, de Bruyn, R, Greeff, L and Vanhaecke, F. 2007. Boron isotope ratio measurements by ICP-MS for classification of wine according to geographical origin. Colloquim Spectroscopium Internationale XXXV, 23-27 September, University Xiamen, China.

Final report
http://www.sawislibrary.co.za/dbtextimages/CoetzeeP.pdf

Coetzee, P, Steffens, F E, Eiselen, R J, Augustyn, O P H, Balcaen, L, Vanhaecke, F. 2005. Multi-element analysis of South African wines by ICP-MS and their classification according to geographical origin. Journal of Agricultural and Food Chemistry. v. 53 n. 13 p. 5060-5066

Article

Coetzee, P, Steffens, F E, Eiselen, R J, Augustyn, O P H, Balcaen, L, Vanhaecke, F. 2005. Multi-element analysis of South African wines by ICP-MS and this classification according to geographical origin. Journal of Agricultural and Food Chemistry. v. 53 n. 13 p. 5060-5066

Coetzee, P P, Vanhaecke, F. 2005. Classifying wine according to geographical origin via based ICP-mass spectrometry measurements of boron isotope ratios. Analytical and Bioanalytical Chemistry. v. 383 n. 6 p. 977-984

Coetzee, P, Augustyn, O P H. 2006. Classification of South African wines according to geographical origin using multi-element chemical analysis. WineLand. Mnth Jan p. 92-95

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