Impact of wine technology on the variability of resveratrol and piceids in Saperavi (Vitis vinifera L.)

The biologically active stilbenoids-resveratrol and its glucosides were identified in the dry bulk wines of different types made with red-grape vintage variety of Saperavi (Vitis vinifera L.): cis-resveratrol, trans-resveratrol, cis-piceid and trans-piceid. Red and pink wines were made by different technology: I - dry, pink, of a European type; alcoholic fermentation with natural microflora; II - dry, pink, of a European type; alcoholic fermentation with dry yeast “B2000”. III - red, dry; alcoholic fermentation with no-stem pomace and aging on it for 5 months; IV - dry, red, of a Kakhetian type; alcoholic fermentation with stem pomace with natural microflora and aging on it for 5 months; V - dry, red, of a Kakhetian type, with preliminary fermentation of cluster stems, then, alcoholic fermentation with natural microflora and aging on it for 5 months. The impact of the wine-making technology on the variability of the concentrations of these substances is proved. Kakhetian bulk wines (IV and V) also differ from one another. Bulk wine-V made by the fermentation of grappa fermented in advance contains little concentration of study stilbenoids as a result of the oxidation transformations caused by the preliminary treatment. The role of grape juice, stem and seed in the localization of resveratrols and piceids in the bulk wines is identified.