Abstract
Sulfur dioxide is used to control the browning of the wine, but it is known as an irritating agent of the digestive mucous membrane, of the lungs, and, at the same time, it destroys the thiamine, therefore the admissible quantities in vinification have been reduced. The research focused on the influence of different SO2 doses on the oxidizing enzymes found in grapes, in the must, and in the young wine. During the alcoholic fermentation the activity of the oxidizing enzymes dropped by 74.3 - 87.5% and the laccase was deactivated when doses of 50 - 75 mg.L-1 SO2 were used. The activity of the polyphenoloxidase (tyrosinase and laccase) gradually decreased during the alcoholic fermentation. Using the same doses of SO2, after the alcoholic fermentation, there has been noted a reduction of 56.6 - 71.8% of the activity of the peroxydase in wine compared to the first day of the alcoholic fermentation.