COMPARATIVE RESEARCHES CONCERNING THE QUALITATIVE CHARACTERISTICS OF THE SUPERIOR WINES DERIVED FROM WINE-GROWING CENTRE OSTROV

Abstract

So as to realize the whole image of the quality evolution of the superior, dry, white wines, derived from wine-growing centre Ostrov, we established the variability estimates of the physical and chemical parameters concerning White Fetească, Italian Riesling and Sauvignon grapes variety of wine, along three succesive crops: 2004, 2005 and 2006. The most increased variability was registered by the Free Sugar parameter (between 34 and 81%), no matter which grapes variety of wine was analysed. The most stable parameters of the three grapes variety of wines, were Density (with a medium variation coefficient, smaller than 1%) and Alcohol content (with a medium variation coefficient, smaller than 4%), parameters which can be considered typical for this category of white wines. The sort of wine which presented the most increased homogenity of the physical and chemical parameters, along the three years investigated, was the Italian Riesling sort. The most heterogeneous values were registered by the Sauvignon sort of wine.

Full text

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Scientific Bulletin, Series F, XIII, Biotechnology, ISSN 1224-7774, Bucharest, 2009
COMPARATIVE RESEARCHES CONCERNING THE QUALITATIVE
CHARACTERISTICS OF THE SUPERIOR WINES DERIVED FROM
WINE-GROWING CENTRE OSTROV
Culea Rodica- Elena *, Popa Nicolae-Ciprian**, Tamba-Berehoiu Radiana*
* University of Agronomic Sciences and Veterinary Medicine of Bucharest (rodica.culea@gmail.com)
**S.C. FARINSAN S.A. Giurgiu
Abstract
So as to realize the whole image of the quality evolution of the superior, dry, white wines, derived from
wine-growing centre Ostrov, we established the variability estimates of the physical and chemical
parameters concerning White Fetească, Italian Riesling and Sauvignon grapes variety of wine, along three
succesive crops: 2004, 2005 and 2006. The most increased variability was registered by the Free Sugar
parameter (between 34 and 81%), no matter which grapes variety of wine was analysed. The most stable
parameters of the three grapes variety of wines, were Density (with a medium variation coefficient, smaller
than 1%) and Alcohol content (with a medium variation coefficient, smaller than 4%), parameters which
can be considered typical for this category of white wines. The sort of wine which presented the most
increased homogenity of the physical and chemical parameters, along the three years investigated, was the
Italian Riesling sort. The most heterogeneous values were registered by the Sauvignon sort of wine.
Key words: White superior wines, physical and chemical characteristics, variability estimates, statistic
differences
INTRODUCTION
The wines produced to SC Ostrovit SA carry the specific nature of this place, with calcareous
soil and droughty climate, with humid atmosphere, due to the Danube influence. In the wine-
growing centre Ostrov, the grapes varieties for wine (especially White Feteasca, Italian Riesling,
Royal Feteasca) are cultivated on a surface counting 245 ha and the grapes varieties for
consumption (Italia, Afuz Ali, Muscat, Hamburg, Sultanina, Moldova) are cultivated on a surface of
936 ha. The wines for current consumption have an Alcohol content of 10-10,4 vol. % and the
superior quality wines, obtained of White Feteasca, Italian Riesling, Merlot, Cabernet, Sauvignon
sorts, have an Alcohol content between 10,5 -10,4 vol. % [1, 5].
The climatic peculiarities, as well as some anthropic elements, which modulate the action of
the environmental agents (applied phytotechny, the cropping moment, the vinification technology
applied), determine the annual variability of the wines’ physical and chemical parameters [3, 4, 6].
This study recommends a comparative qualitative characterization of the dry wines,
obtained of the White Feteasca, Italian Riesling and Sauvignon grapes varieties, made by S.C.
OSTROVIT S.A., in 2004, 2005 and 2006 production years.
MATERIAL AND METHOD
The determinations were made in preceding stage of the wines bottling and
commercialization. There were comparatively anlysed the physical and chemical parameters of
White Feteasca (n=33), Italian Riesling (n = 30) and Sauvignon (n = 31), ingathered from 2004,
2005 and 2006 crops. The following quality parameters of the wine have been analysed: d2020
(picnometric method STAS 6182/8-71), Alcohol % vol. (picnometric method STAS 6182/6-70),
total dry extract mg/l (densimetric method STAS 6182/9-80), Free Sugar g/l (iodometric method
STAS 6182/18-81), Unreducing Extract g/l, Total Acidity g/l C4H6O6 (titrimetric method STAS
6182/1-79), Free SO2 mg/l (iodometric method STAS 6182/13-72) and Total SO2 mg/l (iodometric

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method STAS 6182/13-72) [2,3,4,7]. The obtained results were statistical processed using the
professional program COHORT [2, 7, 8].
RESULTS AND DISCUSSION
The first table shows the variability estimates of physical and chemical parameters,
belonging to White Feteasca sort of wine, concerning the whole investigated period (2004 -2006).
Table 1
The variability estimates of White Feteasca sort of wine samples
corresponding to 2004, 2005 and 2006 crops cumulatively (n = 33)
Parameter
X±s
s
CV %
D2020
0,9937 ± 0,001
0,000001
0,110
Alcohol (vol %)
11,363 ± 0,489
0,239
4,304
Total dry extract (g/l)
23,012 ± 2,150
4,625
9,346
Free sugar (g/l)
2,184 ± 0,749
0,561
34,305
Unreducing extract (g/l)
20,600 ± 2,388
5,703
11,592
Total acidity (g/l C4H6O6)
5,491 ± 0,386
0,149
7,038
Free SO2 (mg/l)
38,696 ± 4,149
17,217
10,722
Total SO2 (mg/l)
129,279 ± 17,731
314,392
13,716
Generally, it is noticed that the physical and chemical parameters of White Feteasca grapes
variety of wine, are not characterized by excesiv values of the variation coefficient, with one
exception, namely the Free sugar parameter (34,305 %).
The second table shows the obtained results in the case of Italian Riesling grapes variety of
wine, concerning the whole investigated period (2004 -2006).
Table 2
The variability estimates of Italian Riesling sort of wine samples
corresponding to 2004, 2005 and 2006 crops cumulatively (n = 30)
Parameter
X±s
s
CV %
D2020
0,9914 ± 0,011
0,000121
1,113
Alcohol (vol %)
11,206 ± 0,297
0,088
2,650
Total dry extract (g/l)
21,493 ± 1,077
1,160
5,012
Free sugar (g/l)
1,268 ± 0,448
0,201
35,358
Unreducing extract (g/l)
20,243 ± 0,948
0,899
4,684
Total acidity (g/l C4H6O6)
5,895 ± 0,274
0,075
4,664
Free SO2 (mg/l)
39,000 ± 5,717
32,689
14,660
Total SO2 (mg/l)
128,733 ± 11,057
122,271
8,589
In this case too, the main parameter which was affected of excesiv variation is also the Free
sugar (35,358 %). In the case of Italian Riesling grapes variety of wine, distinguishes a bit increased
variation coefficient, accordingly to the Free SO2 parameter (14,66 %).
The results, concerning the variability estimates of the analyzed physical and chemical
parameters, in the case of the wine obtained from the Sauvignon grapes variety of 2004-2006 crops,
are presented in the table 3.
Table 3
The variability estimates of Sauvignon sort of wine samples
corresponding to 2004, 2005 and 2006 crops cumulatively (n = 31)
Parameter
X±s
s
CV %

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D2020
0,9937 ± 0,001
0,000001
0,170
Alcohol (vol %)
12,251 ± 0,559
0,313
4,568
Total dry extract (g/l)
25,580 ± 3,135
9,830
12,157
Free sugar (g/l)
3,389 ± 2,770
7,768
81,763
Unreducing extract (g/l)
22,097 ± 0,927
0,859
4,195
Total acidity (g/l C4H6O6)
5,280 ± 0,307
0,094
5,830
Free SO2 (mg/l)
39,966 ± 6,365
40,516
15,926
Total SO2 (mg/l)
145,700 ± 26,241
688,631
18,010
The Free sugar parameter was characterized by a variation coefficient value, higher than 81 %
and the parameters connected to the wine sulphitation operations, had variation coefficients
moreover than 15 %.
Observing the first figure, we noticed that the most stable parameters of the three wines, were
Density (with a medium variation coefficient smaller than 1 %) and the Alcohol content (with a
medium variation coefficient smaller than 4 %). The Free sugar parameter was the most exposed to
variations, no matter the grapes variety, having a medium variation over 50 %.
0.46
8.84
50.48
3.84
13.77
5.84
6.82
13.44
0.00
10.00
20.00
30.00
40.00
50.00
60.00
Density
(D2020)
Alcohol
(vol %)
Total dry
extract (g/l)
Free sugar
(g/l)
Unreducing
extract (g/l)
Total acidity
(g/l C4H6O6)
Free SO2
(mg/l)
Total SO2
(mg/l)
Average of variation coefficients (%)
Figure 1. The variation coefficients average of the physical and
chemical parameters, which characterized the analysed wines
The grapes variety of wine, which presented the most higher homogenity for physical and
chemical parameters, along the three years investigated, was Italian Riesling (the lowest medium
variation coefficient = 9,59 %). The most increased values were registered in the case of Sauvignon
wine, for which it was established a medium variation coefficient of 17,83 % (figure 2). We can say
that the Italian Riesling grapes variety was the best adapted to climatic conditions, which varied
along the analysed period. This sort of wine pointed out the most homogeneous characteristics,
while the Sauvignon wine proved to be the most exposed and misfit.

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11.39
9.59
17.83
0
2
4
6
8
10
12
14
16
18
20
White Feteasca Italian Riesling Sauvignon
Average of variation coefficients (%)
Figure 2. The variation coefficients average of all the parameters, which characterized
every sort of wine (White Feteasca, Italian Riesling and Sauvignon)
The table 4 presents the meaning of averages differences, following the application of the t
test (Student), for all the physical and chemical parameters, in the case of the three studied wines.
Table 4
The meaning of averages differences (t test) of the physical and
chemical parameters concerning the three superior wines
Pairs D2020
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
0,9937
0,9914
1,144
White Feteasca (a) – Sauvignon (b)
0,9937
0,9937
0
Italian Riesling (a) – Sauvignon (b)
0,9914
0,9937
1,163
Pairs Alcohol (%)
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
11,363
11,206
1,563
White Feteasca (a) – Sauvignon (b)
11,363
12,251
6,791***
Italian Riesling (a) – Sauvignon (b)
11,206
12,251
9,154***
Pairs Total dry extract (g/l)
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
23,012
21,493
3,592**
White Feteasca (a) – Sauvignon (b)
23,012
25,580
3.797***
Italian Riesling (a) – Sauvignon (b)
21,493
25,580
6,852***
Pairs Free Sugar (g/l)
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
2,184
1,268
5,950***
White Feteasca (a) – Sauvignon (b)
2,184
3,389
2,394*
Italian Riesling (a) – Sauvignon (b)
1,268
3,389
4,181***
Pairs Unreducing extract (g/l)
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
20,600
20,243
0.792
White Feteasca (a) – Sauvignon (b)
20,600
22,097
3.342*
Italian Riesling (a) – Sauvignon (b)
20,243
22,097
7,722***
Pairs Total acidity (g/l C4H6O6)
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
5,491
5,895
4,744***
White Feteasca (a) – Sauvignon (b)
5,491
5,280
2,411*
Italian Riesling (a) – Sauvignon (b)
5,895
5,280
8,252***
Pairs Free SO2
Average (a)
Average (b)
t

5
White Feteasca (a) – Italian Riesling (b)
38,696
39,000
0,243
White Feteasca (a) – Sauvignon (b)
38,696
39,966
0,939
Italian Riesling (a) – Sauvignon (b)
39,000
39,966
0,692
Pairs Total SO2
Average (a)
Average (b)
t
White Feteasca (a) – Italian Riesling (b)
129,279
128,733
0,148
White Feteasca (a) – Sauvignon (b)
129,279
145,700
2,914**
Italian Riesling (a) – Sauvignon (b)
128,733
145,700
3,309**
As noticeable from the table 4, the Density parameter did not differ significantly between
neither one of the analysed wine pairs. This fact shows that the parameter Density is rather typical
for the wines category (white, dry wines), than for the grapes variety of wines, respective White
Feteasca, Italian Riesling or Sauvignon.
One can also see, that the Alcoholic Content % did not differ significant between the White
Feteasca and Italian Riesling grapes varieties of wines. However, the White Feteasca and Italian
Riesling grapes varieties of wines, had a very significant low alcoholic concentration, comparative
to the Sauvignon grapes variety of wine.
The parameter Total dry extract was very significant different between the three grapes
varieties of wine. The highest value was registered to Sauvignon grapes variety (25,58 %), followed
by White Feteasca grapes variety (2,184 g/l) and Italian Riesling grapes variety (21,493 %).
The parameter Free sugar presented a grapes variety specificity, having significant and very
significant different values between the wines. The highest value one can see in the case of
Sauvignon grapes variety (3,389 %), followed by White Feteasca grapes variety (2,184 g/l) and
Italian Riesling grapes variety (1,268 g/l).
Regarding the Unreducing extract parameter, it was noticed that registered values, in the
case of White Feteasca and Italian Riesling grapes varieties of wines, did not differ significant.
Instead, the Sauvignon and White Feteasca, respective Italian Riesling grapes varieties of wines,
differed significant and very significant. So, the highest value of the Unreducing extract parameter
was specific to Sauvignon grapes variety of wine, followed by White Feteasca and Italian Riesling
grapes varieties of wine.
The Total Acidity parameter could also be considered as being peculiar to every grapes
varieties of wines. Matter of fact, all grapes varieties of wines presented at least significant
differences between the values of this parameter. White Feteasca grapes variety of wine presented a
very significant decreased value of Total Acidity, comparative to Riesling Italian grapes variety of
wine and a significant grown value, comparative to Sauvignon grapes variety of wine. The Italian
Riesling grapes variety of wine presented a very significant grown value of the Total Acidity,
comparative to Sauvignon grapes variety of wine. The highest values of this parameter were
peculiar to the Italian Riesling grapes variety of wine, followed in order by the White Feteasca and
Sauvignon grapes varieties of wines.
The analysed grapes varieties of wine did not differ concerning the Free SO2 quantities,
though appeared some distinctly significant differences between Sauvignon and White Feteasca or
Italian Riesling grapes varieties of wines. These differences due to the higher quantity of Total SO2
present in the Sauvignon grapes variety of wine, comparative with other two sorts of wines.
Our analysis showed that the least peculiar parameters of the grapes variety of wine were the
Density and the Free SO2 content. In practice, the values of these parameters seem rather
characteristics of the wine category, respective superior, white, dry wines, then grapes variety
characteristics. Instead, prameters as: Total Dry Extract, Free Sugar or Total Acidity presented
significant differences between each pair of analysed grapes varieties. The fact is showing that the
value of these parameters could be considered typical for every sort of wine.

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CONCLUSIONS
 The wine obtained of White Feteasca grapes variety had the quality parameters values
specific to superior, white and dry wines. The physical and chemical parameters did not present
excessive values of the variation coefficients, single exception being the Free Sugar parameter
(CV=34,305 %).
 Concerning the Italian Riesling grapes variety, the values of the quality parameters were
typical for superior, white and dry wines. The main parameter which was affected by excessive
variations was also, the Free sugar (CV=35,358 %). Concomitantly, we can observe the existence of
an easily growning variation, in the case of Free SO2 parameter (8,589 %).
 The Sauvignon grapes variety of wine, pointed out quality parameters suitable to superior,
white and dry categories of wines, but there were affected by increased variations. So, the Free
Sugar parameter showed a variation coefficient value higher than 81 %. A rather increased variation
coefficient was observed at the parameters connected to the wine sulphitation, moreover than 15 %.
 The Italian Riesling grapes variety was the best adapted to climatic conditions, peculiar to
2004-2006 period. So, the wine produced of Italian Riesling grapes variety, revealed homogenous
characteristics.
 The Sauvignon grapes variety of wine proved to be the most exposed and misfit.
 We may assert that the Density, Alcoholic content and Free SO2 parameters are peculiar
to superior, white and dry wines, while the Total Dry Extract, Free Sugar and Total Acidity
parameters could be considered typical for every sort of wine.
REFERENCES
1. COTEA, V.D., GRIGORESCU, C., BARBU, N., COTEA, V.V., 2000, Podgoriile si vinurile României,
Editura Academiei Române
2. COTOFREI, S. C., 2004, Cercetari privind optimizarea metodologiei de calcul matematic in oenologie,
Teză de doctorat, Iaşi
3. IONESCU, I.A., 1968, Factorii ce determină calitatea vinurilor, Revista Horticultura şi Viticultura nr. 2,
Bucureşti
4. KONTEK, A., KONTEK, Ad., 1999, Măsuri tehnologice care contribuie la îmbunătăţirea calităţii
vinurilor albe seci, Concepţii moderne în cercetarea horticolă Românească, Editura Medro.
5. POMOHACI, N.,NĂMOLOŞANU, I., NĂMOLOŞANU, A., 2000, Producerea şi îngrijirea vinurilor,
Editura Ceres, Bucureşti, pg. 27-31.
6. POMOHACI, N., SÎRGHI,C.., STOIAN, V., COTEA, V.,NĂMOLOŞANU, I., 2000, Oenologie,
Editura Ceres, Bucureşti, pg 132.
7. SNEDECOR, G.W., COCHRAN, W.G., 1989. Statistical Methods. Iowa State University Press, Ames,
IA, USA.
8. **** Culegere de Standarde Române comentate / Metode de analiză, I.R.S. Institutul Român de
standardizare, Bucureşti, 1997.