Page last updated: Tuesday, November 18, 2008
More about white wines and their contents
by Gordon J. Troup, School of Physics, Monash University, Clayton 3800, Victoria, Australia.

In the early days of the research on the salutary effects of moderate wine drinking, Jack Masquelier, the discoverer and researcher of the effects of the small numbered polymers of the polyphenols in (red) wines could say: “Drink red wine for your health and white wine for your enjoyment” [1], because all the salutary effects of wine were supposed to come from these compounds, which white wines were denied in the making, unless they were left on the seeds and skins for a while. Clinical studies showed that red wine certainly reduced the ratio of the ‘bad ‘ cholesterol (LDL) to the ‘good’ (HDL) in the blood stream, but there were also studies, e.g. [2], that showed that certain white wines (low in total phenolics) had the opposite effect, while others were not as efficient as the red ones. Research was started on the other molecules, mainly monophenols, for their salutary effects.

An account of some of the very interesting findings are given below. These were obtained mainly from the two papers [3, 4] summarised in the July edition of AIM-Digest: [4] was ‘in press online’ at the time, and so not available immediately then.

Two monophenols, tyrosol and hydroxytyrosol, develop in wine during the fermentation process, and are not found in the grape: they are good antioxidants. Because they are small, they can take part in chemical reactions that the polyphenols cannot, such as helping in a healing pathway for heart tissue after a heart attack, and strengthening the tissue in the first place. Another molecule, shikimic acid, which has a hexagonal (but not phenolic) ring with 3 hydroxyls on it, is also a good antioxidant. It can be a forerunner for polyphenols and tannins.

Masquelier [1] tended to put most of the blame for tissue damage and cell damage on the superoxide radical ( O2- ), which is needed for certain chemical reactions in our bodies, but can run amok. It is now known that this radical is in fact less toxic to cells than the hydroxyl radical .OH, a reactive oxygen species radical (ROS). In fact it is stated in [3] that “Virtually all the biomolecules including simple carbohydrates, lipids, proteins and DNAs are potential targets for hydroxyl radical attack”. Fortunately, simple sugars and acids such as malic acid, tartaric acid and shikimic acid are themselves antioxidants and contained in white wines. Of course, the content will depend on the white wine and the treatment it has received. In [4], the white wine used was Soave DOC Classico 2004 (Le Rive), which was found to have a higher content of tyrosol and shikimic acid than other white wines.

More work needs to be done in the area of characterising which white wines, if combined with a good (Mediterranean) diet, cause the LDL/HDL cholesterol ratio to increase rather than decrease. Research continues on resveratrol with very promising results for it to be an anti-aging agent.

References

[1] B.Schwitters and J.Masquelier, ‘O P C in Practice’, 2nd edition, 1995, Alfa Omega Editrice, Roma, Italy, p.80.

[2] E.P.Mansvelt, D.P.van Velden et al., Ann.N.Y. Acad. Sci.2002, 957, 329.

[3] M.Falchi, A .Bertelli…and Dipak M. Das, J.Agric.Food Chem. 2006, 54, 6613.

[4] M.Thirunavukkarasu,…A.Bertelli,..and N.Malik,J.Agric. Food Chem. 2008, 56, 6733.

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