Abstract:
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Wine has already been investigated for its potential nutritional quality, such as high amount of
phenolic compounds. Phenolic compounds, well-known as natural antioxidants, are reported due
their radical scavenging capacity.
In the present work, the bioactive ingredients of nine Austrian wines (four red wines: Zweigelt,
Blaufränkisch, Syrah and Cuvée; two white wines: Pinot Blanc and Chardonnay; one rosé
Blaufränkisch; and two grape juice: red and white) have been quantified and the antioxidant activity
has been evaluated.
Among the bioactive compounds the total amount of polyphenols, flavonoids, catechins, and
proanthocyanidins, were studied and analyzed by standardized photometric methods. The
antioxidant activity was determined by the DPPH· radical scavenging method as well as by ABTS
assays. The results of the antioxidant capacity were expressed using the term EC50 and Trolox
equivalents.
As expected, red wines have higher phenolic content (Total polyphenols: 2211,76 mg gallic acid
equivalents (GAE)/l, Flavonoids: 1418,39 mg catechin equivalents/l, Catechins: 635,36 mg catechin
equivalents/l, 82,15 mg cyanidin equivalents/l for Cuvée) and antioxidant activity (DPPH: EC50 = 0,21 ml
sample/mg DPPH and Trolox equivalents = 1,1 ml sample/mg Trolox; ABTS: EC50 = 2,50 ml sample/l ABTS and
Trolox equivalents = 0,7 ml sample/mg Trolox) than rosé Blaufränkisch (Total polyphenols: 315,44 mg GAE/l,
Flavonoids: 76,78 mg catechin equivalents/l, Catechins: 9,05 mg catechin equivalents/l, Proanthocyanidins: 1,69
mg cyanidin equivalents/l; DPPH: EC50 = 2,52 ml sample/mg DPPH and Trolox equivalents = 13,2 ml sample/mg
Trolox; ABTS: EC50 = 109,22 ml sample/l ABTS and Trolox equivalents = 31,1 ml sample/mg Trolox), white wines
(Total polyphenols: 333,76 mg GAE/l, Flavonoids: 74,02 mg catechin equivalents/l, Catechins: 14,27 mg catechin
equivalents/l, Proanthocyanidin: 1,07 mg cyanidin equivalents/l; DPPH: EC50 = 2,74 ml sample/mg DPPH and
Trolox equivalents = 14,3 ml sample/mg Trolox; ABTS: EC50 = 83,33 ml sample/l ABTS and Trolox equivalents =
23,7 ml sample/mg Trolox for Chardonnay) and grape juice (Total polyphenols: 710,35 and 110,22 mg GAE/l,
Flavonoids: 313,56 and 8,28 mg catechin equivalents/l, Catechins: 133,64 and 1,06 mg catechin equivalents/l,
Proanthocyanidin: 11,63 and 6,93 mg cyanidin equivalents/l; DPPH: EC50 = 1,34 and 15,02 ml sample/mg DPPH
and Trolox equivalents = 7 and 78,7 ml sample/mg Trolox; ABTS: EC50 = 319,77 and 650 ml sample/l ABTS and
Trolox equivalents = 5,6 and 184,9 ml sample/mg Trolox for red and white, respectably). The relationship
between the phenolic contents and the antioxidant activity in each sample was also checked. The
results gave a slightly tendency (R > 0,8 for DPPH assay and R > 0,6 for ABTS assay).
Finally, it was observed that Cuvée wine has the highest antioxidant capacity for each method used
and that the content of phenolic compounds in Austrian wines is very similar to Chinese wines and
lower than those in the Italian wines. |