| A study was conducted to examine oxidative changes in bottle-fermented sparkling wines during the secondary fermentation and also post-disgorgement. Both Vitis vinifera and hybrid wine grape cultivars were used. Treatments included levels of ascorbic acid, sulfur dioxide and combinations of the two. For the post-disgorgement study, wines were stored 11 months at 21{dollar}spcirc{dollar}C, before the analysis. Oxidative parameters such as absorbance, color and acetaldehyde were measured, along with phenolics and residual ascorbic acid. Acetaldehyde was highest in the sulfur dioxide treatments, while browning was lowest in these. Ascorbic acid had a good degree of stability in the wines, with 52% to 70% of the original amount added remaining after storage. An accelerated browning test showed the ascorbic acid treatments had the highest potential for oxidation if exposed to high levels of oxygen and increased temperature. In the study examining oxidation during the secondary fermentations, added ascorbic acid reduced sulfur dioxide levels present in the wines. The ascorbic acid added had good stability during this period of bottle-fermentation. Added SO{dollar}sb2{dollar} at time of inoculation for the secondary fermentations resulted in increased acetaldehyde levels. |
