conference schedule and program with abstracts - Horticulture ...

P-6
Polyphenolic potential of the rare Croatian variety ‘Dobricic’ (Vitis vinifera L.)
I. Budic-Leto*, G. Zdunic, I. Tomic-Potrebujes
Institute for Adriatic Crops and Karst Reclamation, Split, Croatia
*Corresponding author: irena@krs.hr
Croatia is very rich in grapevine (Vitis vinifera L.) biodiversity and many native varieties have
been grown mostly along the Dalmatian coast from ancient times. Many of the old native
varieties have almost vanished and Dobricic is one of them. This variety has a great potential to
be used in planting new vineyards, but its enological characteristics still have not been defined
and its wine is still not available on the Croatian market. Polyphenolic compounds are of
profound significance for determining technological and nutritional values as well as sensorial
properties of grapes and wines. In this work, the phenolic potential of Dobricic grapes has been
evaluated and the influence of its polyphenols on the colour and composition of the wines has
been established. Two different vineyards with this variety were considered. Three samples from
each vineyard were taken at the moment of harvest. Simulated maceration assays were carried
out in wine model solutions containing 12 vol% ethanol, 5 g/L of tartaric acid and 50 mg/L of
SO 2 , neutralized with 1/3 M NaOH to pH 3.2 in order to investigate the composition of the
fraction of polyphenols that are extracted from the grape into the wine. For each sample, separate
extraction assays were performed using the grape skin and seeds. The results show that grape
extract of this rare native variety contains appreciable amount of total phenols (on average 3585
mg/kg), proanthocyanidins (4251 mg/kg) and catechins (2718 mg/kg) as well as anthocyanins
(on average 1341 mg/kg). It was determined that grape skin is rich mainly in high-molecularmass
proanthocyanidins, while an average of 21% of proanthocyanidins is contained in the seed.
The skin contained higher concentration of low-molecular-mass proanthocyanidin than the seeds,
as determined by vanillin index. Wines from this variety presented high colour intensity. The
correlations between the polyphenolic potential of the grapes and the extractability of the
proanthocyanidins, catechins and anthocyanins into the wine during the winemaking process
showed good agreement.
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