Project title
Evaluation of the antioxidant potential of the major South African red and white wines

Project leader
Joubert, E

Institution
ARC Infruitec-Nietvoorbij

Team members
Marais, J
Redelinghuys, H E

Project description
The aim of this project is to determine the antioxidant potential of the major South African red and white wines as affected by cultivar, in bottle ageing and production area. The free radical scavenging activity of South African red and white cultivar wines was determined using the ABTS radical cation and the DPPH radical scavenging assays. Inhibition of lipid peroxidation by these wines was tested in a microsomal system used as a membrane model of biological relevance. The antioxidant activity of red wine as radical scavenger was much higher than that of white wine on an ?as is? basis, as well as at the same total phenol content. This indicated not only that the total phenol content, but also the type and/or concentration of individual polyphenols present in red wines, is more effective than that of white wines. The total antioxidant activity of Ruby Cabernet wines was lower than that of other red cultivar wines, in spite of the highest monomeric anthocyanin content, while Chardonnay and Chenin blanc wines had the highest and lowest total antioxidant activity of white cultivar wines respectively. The antioxidant activity of both red and white wines correlated (P < 0.001) with their total phenol content. The main phenolic groups correlating (P < 0.001) with antioxidant activity were flavanols for red wines and tartaric acid esters for white wines. Anthocyanin content did not correlate with free radical scavenging activity of the red wines. Canonical discriminant analysis aided differentiation of red and white cultivar wines on the basis of parameters for phenolic composition, as well as antioxidant activity.

Inhibition of microsomal lipid peroxidation showed broadly the same pattern than the free radical scavenging assays, with Ruby Cabernet performing the poorest inhibition of the red cultivar wines. Similar to the free radical scavenging assays, the anthocyanin content did not correlate with inhibition of lipid peroxidation. At equal polyphenol concentration, the red wine (Pinotage) was more potent as inhibitor of lipid peroxidation than the white wine (Chardonnay). This effect will be even more enhanced on an 'as-is' basis.

No differentiation between wines on the basis of production area was possible. This is attributed to large variation within cultivars due to external factors. Ageing and analyses of these wines were carried out as planned.

Poster(s)
1. De Beer, D, Joubert, E, Gelderblom, W C A and Manley, M. 2001. Antioxidant activity of South African red and white wines: Inhibition of microsomal lipid peroxidation. 25th National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.
2. De Beer, D, Joubert, E, Gelderblom, W C A and Manley, M. 2001. Antioxidant activity of South African red and white wines: Inhibition of microsomal lipid peroxidation. 16th Biennial International Congress and Exhibition, 10-12 September, Durban, South Africa.
3. De Beer, D, Waterhouse, A L, Joubert, E, Marais, J and Manley, M. 2003. Standardisation of wine analysis: Sample management to prevent loss of phenolic compounds. 27th National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.
4. De Beer, D, Joubert, E, Marais, J, Van Schalkwyk, D and Manley, M. 2003. The effect of climate and vine management systems on the phenolic composition and total antioxidant capacity of Pinotage wines: Preliminary results. 27th National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.
5. De Beer, D, Joubert, E, Marais, J, Van Schalkwyk, D and Manley, M. 2003. The effect of climate and vine management systems on the phenolic composition and total antioxidant capacity of Pinotage wines: Preliminary results. 17th SAAFoST International Congress and Exhibition, September, Pretoria, South Africa.
6. De Beer, D, Joubert, E, Gelderblom, W C A and Manley, M. 2003. In-bottle maturation of red and white wines: Changes in phenolic composition and antioxidant activity. 17th SAAFoST International Congress and Exhibition, September, Pretoria, South Africa.
7. De Beer, D, Joubert, E, Marais, J and Manley, M. 2004. Contribution of phenolic compounds to the total antioxidant capacity of Pinotage wine. XXIIth International Conference on Polyphenols, August, Helsinki, Finland.
8. De Beer, D, Joubert, E, Marais J and Manley, M. 2005. Contribution of phenolic compounds to the total antioxidant capacity of Pinotage wine. 18th Biennial SAAFoST Congress and Exhibition, September, Stellenbosch, South Africa.

Presentation(s)
1. De Beer, D, Joubert, E, Gelderblom, W C A and Manley, M. 2001. The effect of accelerated in-bottle ageing on the antioxidant activity of red and white wines. 25th National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.
2. De Beer, D, Joubert, E, Gelderblom, W C A and Manley, M. 2001. Comparison of the free radical scavenging activities of South African red and white wines. SAAFoST 16th Biennial International Congress and Exhibition, 10-12 September, Durban.
3. Joubert, E. 2002. Suid-Afrikaanse wyne as bron van antioksidante. Radio Elsenburg, 10 May.
4. De Beer, D, Joubert, E, Van Schalkwyk, D, Marais, J, Gelderblom, W C A and Manley, M. 2003. Antioxidant capacity of wine: Effect of viticultural and oenological practices on phenolic composition and quality. SAAFoST Congress.
5.  De Beer, D, Fourie, B, Joubert, E, Du Toit, W, Marais, J and Manley, M. 2003. Wood maturation of Pinotage using barrels and alternative wood products: Effect on phenolic composition and antioxidant activity. 27th National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.
6. De Beer, D, Joubert, E, Van Schalkwyk, D, Marais, J, Gelderblom, W C A and Manley, M. 2003. Antioxidant capacity of wine: Effect of viticultural and oenological practices on phenolic composition and quality. 17th SAAFoST Congress, September, Pretoria, South Africa.
7.  De Beer, D, Joubert, E, Marais, J and Manley, M. 2005. Contribution of phenolic compounds to the total antioxidant capacity of Pinotage wine. 3rd International Congress of the South African Society for Enology and Viticulture, November, Cape Town.
8. De Beer, D, Joubert, E, Marais, J and Manley, M. 2005. Contribution of phenolic compounds to the total antioxidant capacity of Pinotage wine. International Congress of the South African Society for Enology and Viticulture, November, Cape Town, South Africa
9. De Beer, D, Joubert, E, Marais, J, and Manley, M. 2005. Unravelling the total antioxidant capacity of Pinotage wines - the contribution of phenolic compounds and the role of synergism. International Congress on Health and Wine: Vindaba, September, Stellenbosch, South Africa.
10. De Beer, D, Joubert, E, Marais, J and Manley, M. 2005. Guidelines for the production of Pinotage wine with optimal antioxidant capacity while retaining sensory quality. 3rd International Congress of the South African Society for Viticulture and Enology Congress, November, Somerset West, South Africa.

Final report
http://www.sawislibrary.co.za/dbtextimages/FinalReport128.pdf

De Beer, D E, Joubert, E, Gelderblom, W C A, Manley, M. 2002. Phenolic compounds a review of their possible role in vivo antioxidants of wine. South African Journal of Enology + Viticulture. v. 23 n. 2 p. 48-61

Article

De Beer, D E, Joubert, E, Gelderblom, W C A, Manley, M. 2003. Antioxidant activity of South African red and white cultivar wines: free radical scavenging. Journal of Agricultural and Food Chemistry. v. 51 n. 4 p. 902-909

De Beer, D E, Harbertson, J F, Kilmartin, P A, Roginsky, V, Barsukova, T, Adams, D O, Waterhouse, A L. 2004. Phenolics: a comparison of diverse analytical methods. American Journal of Enology + Viticulture. v. 55 n. 4 p. 389-400

De Beer, D E, Joubert, E, Gelderblom, W C A, Manley, M. 2005. Antioxidant activity of South African red and white cultivar wines selected wine phenolic compounds: Inhibition of microsomal lipid peroxidation. Food Chemistry. v. 90 n. 4 p. 569-577

De Beer, D E, Joubert, E, Gelderblom, W C A, Manley, M. 2005. Changes in the phenolic composition and antioxidant activity of Pinotage, Cabernet Sauvignon, Chardonnay and Chenin blanc wines during bottle ageing. South African Journal of Enology + Viticulture. v. 26 n. 1 p. 6-15

De Beer, D, Joubert, E, Marais, J, Manley, M. 2006. Maceration before and during fermentation: Effect on Pinotage wine phenolic composition, total anti-oxidant capacity and objective colour parameters. South African Journal of Enology + Viticulture. v. 27 n. 2 p. 137-150

De Beer, D, Joubert, E, Marais, J, Manley, M. 2006. Climate, region and vine structure: Effect on Pinotage wine phenolic composition, total anti-oxidant capacity and colour. South African Journal of Enology + Viticulture. v. 27 n. 2 p. 151-166

De Beer, D, Joubert, E. 2006. Anti-oxidant activity of South African red and white cultivar wines. WineLand. Mnth Apr n. 200 p. 62-64

De Beer, D E, Joubert, E, Marais, J, Manley, M. 2006. Unravelling the total antioxidant capacity of Pinotage wines: contribution of phenolic compounds. Journal of Agricultural and Food Chemistry. v. 54 n. 8 p. 2897-2905

Roginsky, V, De Beer, D E, Harbertson, J F, Kilmartin, P A, Barsukova, T, Adams, D O, Waterhouse, A L. 2006. The antioxidant activity of Californian red wines does not correlate with wine age. Journal of the Science of Food and Agriculture. v. 86 n. 5 p. 834-840

De Beer, D E. 2006. Antioxidant capacity of Pinotage wine as affected by viticultural and enological practices. PhD. University of Stellenbosch.

Dissertation

De Beer, D E. 2002. The antioxidant activity of South African wines in different test systems as affected by cultivar and ageing. M.Sc.

Thesis

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