Resumen de Polyphenolic potential of the rare croatian cultivar 'dobricic' (vitis vinifera l.)
Goran Zdunić, Irena Budic-Leto, Iva Tomic-Potrebujes
Croatia is very rich in grapevine (Vitis vinifera L.) biodiversity and many native cultivars have been grown from ancient times, mostly along the Dalmatian coast. Many of the old native cultivars have almost vanished and ?Dobricic? is one of them. This cultivar has a great potential to be used in planting new vineyards, but its oenological 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 sensory properties of grape cultivars and wines. In this work, the phenolic potential of ?Dobricic? grapes has been evaluated. Two different vineyards with this cultivar were considered. Three samples from each vineyard were taken at the time of harvest. Simulated maceration assays were carried out in model wine solutions containing 12% ethanol, 5 g/L of tartaric acid and 50 mg/L of SO2, neutralized with 0.3 M NaOH to pH=3.2 in order to investigate the composition of the polyphenols that were 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 cultivar contains appre-ciable amount of total phenols, proanthocyanidins and catechins as well as antho-cyanins. It was determined that grape skin is rich mainly in high-molecular-mass proanthocyanidins and anthocyanins. The skin contained higher concentration of low-molecular-mass proanthocyanidins than the seeds, as determined by vanillin index.
