Effect of sulfur dioxide addition in wild yeast population dynamics and polyphenolic composition during spontaneous red wine fermentation from Vitis vinifera cultivar Agiorgitiko

摘要

The aim of the present study was to assess the effect of sulfur dioxide addition in the wild yeast population dynamics as well as the polyphenolic composition during spontaneous red wine fermentation from Vitis vinifera cultivar Agiorgitiko. The grapes were crushed and fermentation took place at 21 A degrees C without the addition of any commercial yeast, and with and without the addition of 40 mg L-1 SO2. A combination of culture-dependent and culture-independent techniques was used for wild yeast population dynamics assessment and HPLC analysis for the determination of polyphenolic compounds. Regarding the former, the effect of sulfur dioxide addition was only marginal since Saccharomyces cerevisiae strains dominated the fermentation from the first day; strains belonging to Hanseniaspora spp., Lachancea thermotolerans and Metschnikowia pulcherrima species appeared only occasionally. As far as the polyphenolic content was concerned, it was enhanced with sulfur dioxide addition; however, as time progressed, the differences were reduced, suggesting that the time the juice was in contact with the skins was of greater importance than sulfur dioxide addition.