CHARACTERIZING TURKISH WINES BY THEIR PHENOLIC CONSTITUENTS

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CHARACTERIZING TURKISH WINES BY THEIR PHENOLIC
CONSTITUENTS Nese SAHIN-YESILCUBUK, Artemis
KARAALI Istanbul Technical University, Department
of Food Engineering, Istanbul, TURKEY e-mail
sahinnes_at_itu.edu.tr, karaali_at_itu.edu.tr
ABSTRACT
INTRODUCTION
Wine samples (13 red, 2 rose, and 6 white)
obtained from different representative regions of
Turkey and from different grape varieties were
examined. Total phenolic contents were determined
by Folin-Ciocalteu method and antioxidative
potentials were analyzed by DPPH and ABTS assays.
In addition HPLC analyses were carried out to
characterize the phenolic profiles of wines.
Total phenolic contents were found to range
between 1163.9-2538.3, 338.78-800 and 132.5-418.7
mg GAE/L for red, rose and white wines,
respectively. Average DPPH radical scavenging
activity was found to be highest (81.3) for red
wines, followed by rose (22.3) and white wines
(7.5). The average antioxidant activities
determined by ABTS method were found to be 236,
81 and 63 mmol TEAC/L for red, rose and white
wines, respectively. A good correlation (r 0.97)
was obtained with the antioxidative activity and
total phenol content. Furthermore, the
chromatographic profiles allowed separation and
quantification of phenols from different groups.
Phenolic acids present included predominantly
gallic, hydroxybenzoic, syringic, caffeic,
ferulic, and p-coumaric acids. The results
suggest that, Turkish red wines have considerable
amounts of phenolics compared to the wines from
different regions of the world. The results will
also contribute to future studies for developing
wines with high antioxidative potentials.
Grapes and wines, especially the red ones,
contain high amounts of polyphenols, currently
recognized as natural antioxidants responsible
for in vivo anticarcinogenicity and
antimutagenicity effects, as well as showing
significant protective action against
cardiovascular diseases. Phenolic compounds
include phenolic acids, coumarins, flavonoids,
tannens and lignans. Turkey is one of the
important grape producer countries in the world.
In 2006, the annual production was 3.650.000
tonnes and Turkey was ranked as the 6th country
(FAOSTAT, 2006). Although the grape production is
high in Turkey, wine production is not as high as
expected. But nowadays, the wine industry is
fastly growing. It is necessary to characterize
Turkish wines in order to obtain data about the
wine varities for the wine industry. Our
objective was to investigate the total phenol
contents, antioxidant potentials and as well as
to characterize the phenolic constituents of
Turkish wines.
RESULTS AND DISCUSSION
MATERIALS AND METHODS

• Materials
• 13 red, 2 rose, 5 white and 1 sparkling wine
  samples, obtained from different representative
  regions of Turkey and from different grape
  varieties as shown in Table 1 and Figure 1.

• Total Phenolic contents Total phenolic contents
  were found to range between 1163.9-2538.3,
  338.78-800 and 132.5-418.7 mg GAE/L for red, rose
  and white wines, respectively. The average of
  total phenolic contents of red, rose and white
  wines were found to be 1963,9 mg GAE/L, 569,4 mg
  GAE/L and 265 mg GAE/L, respectively.

• The phenolic contents of red wines were
  consistent with the values of different
  reserachers (Arnous et al., 2001 Minussi et al.,
  2003 Lopez et al., 2001).
• Grape varieties grown in Thrace, East Turkey,
  Southeast Turkey, Aegean, and Central Anatolia
  resulted in red wines with similar phenolic
  contents from different countries.
• Phenolic content of rose wines were lower
  compared with the results of Minussi et al.
  (2003).
• White wines produced from grapes grown in Aegean,
  Thrace and Capadocia regions had similar phenolic
  contents found by various reserachers (Minussi et
  al., 2003 Recamales et al., 2006).

Table 1 Wine samples
Figure 2 Total phenolic contents of wine samples

• DPPH Activity Average DPPH radical scavenging
  activity was found to be highest (81.3) for red
  wines, followed by rose (22.3) and white wines
  (7.5).

• DPPH activity of white wines were lower compared
  with results (12.7) of Katalinic et al. (2006).
  
• DPPH acitivity of red wines were higher than
  results of Katalinic et al. (2006) (70.9 ).

Figure 3 DPPH activity of wine samples

• ABTS Activity The average antioxidant activities
  determined by ABTS method were found to be 236,
  81 and 63 mmol Trolox Equivalent Antioxidant
  Capacity (TEAC)/L for red, rose and white wines,
  respectively.

• Pachon et al. (2004) found ABTS activity as 0,64
  mmol TEAC for white wines and 6,93 mmol TEAC for
  red wines.
• Since concentration is not indicated, no
  comparison could be made.

Grape origins
Samples 1, 2, 3, 6, 7, 9,10, 13,14, 20, 21
Samples 2, 5, 8, 11
Figure 4 ABTS activity of wine samples

• Correlation

Samples 11, 12, 13, 14, 15, 16, 18, 21

• Good correlation was observed for total phenolic
  contents and antioxidant activity.
• Correlation coefficients (r) with the
  antioxidative activity (DDPH and ABTS assays) and
  total phenol content were obtained as 0,97 and
  0,91.

Samples 1, 3,7, 8, 12
Samples 4, 17
Figure 1 Grape origins of wine samples
Figure 5 Correlation between phenolic content
with DPPH and ABTS

• Methods
• Total phenolic content Determined by
  Folin-Ciocalteu method. Red and rose wines were
  diluted by 120 and white and sparkling by 110
  ((Spanos and Wroldstad, 1990).
• Antioxidative potentials Were analyzed by DPPH
  and ABTS assays. All samples were diluted by
  110.
• HPLC analyses Were carried out to characterize
  the phenolic profiles by using C18 HPLC column
  and photodiode array detection.

• HPLC Chromatogram HPLC analyses were carried out
  to characterize the phenolic profiles by using
  C18 HPLC column and photodiode array detection.

• The chromatographic profiles allowed separation
  and quantification of phenols from different
  groups.
• Phenolic acids present included predominantly
  gallic, hydroxybenzoic, syringic, caffeic,
  ferulic, and p-coumaric acids.

• REFERENCES
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Figure 6 HPLC chromatogram of a red wine sample
8.
ACKNOWLEDGEMENT The authors gratefully
acknowledge the financial support from the EU
6th Framework STREP Project FLORA (Flavonoids And
Related Phenolics For Healthy Living Using Orally
Recommended Antioxidants).