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G. Kroyer:
"Polyphenols and antioxidant activity of selected Austrian wines and grape juice";
in: "Proccedings of the 7th Symposium In Vino Analytica Scientia", issued by: Technische Universität Graz; Technische Universität Graz, Graz, 2011, (invited), ISBN: 978-3-85125-166-1, 128.

There is a growing interest in the food industry and in preventive health care in the development of natural antioxidants from plant materials. Consumption of a diet rich in antioxidant active polyphenol compounds has been linked with a beneficial health impact. Products from viniculture are an interesting source of bioactive polyphenol compounds which are well known for their antioxidant and radical scavenging properties.
The objective of this study was to determine the content of total polyphenols and proanthocyanidins in selected red and white wines of the different grape varieties "Zweigelt", "Blaufränkisch", "Syrah", "Cuvee (Cabernet Sauvignon, Merlot, Zweigelt, Blaufränkisch)", "Chardonnay", "Pinot Blanc" as well as red and white grape juice cultivated and produced regionally in Austria. Furthermore, their antioxidant activity and radical scavenging ability is evaluated which is suggested to be responsible for their positive health benefits.
The wine and juice varieties were analyzed regarding their content of total polyphenols and proanthocyanidins by photometric methods. The radical scavenging activity was determined with the DPPH* radical scavenging method in terms of their Efficient Concentration EC 50 (ml wine/mg DPPH) and their Trolox Equivalent Antioxidant Capacity TE (mMol Trolox/l) .
Above all the red wine varieties showed remarkable amounts of total polyphenols (1594 - 2211 mg/l) and proanthocyanidins (70 - 86 mg/l) compared to white wine (278 - 334 mg/l, respectively 0,7 - 1,1 mg/l). The grape juices showed lower but still remarkable contents of total polyphenols and proanthocyanidins which were more pronounced in red grape juice (710 and 12 mg/l, respectively) than in white grape juice (110 and 7 mg/l, respectively).
Correlating with the total polyphenol content, the highest antioxidant and radical scavenging capacity was observed in the red wine varieties (2,5 - 3,6 TE). The white wine varieties showed relatively poor inhibitory effectiveness (0,23 - 0,28 TE) as well as red and white grape juice (0,57 and 0,05 TE, respectively).
The results indicate that consumption wine especially red wine due to their significant content of polyphenols and proanthocyanidins and remarkable radical scavenging properties offer a potential beneficial impact in maintaining and promoting health.

wine, grape juice, polyphenols, antioxidant activity

http://publik.tuwien.ac.at/files/PubDat_201029.docx