Influence of the addition of sulphur dioxide and must hyperoxidation on the phenolic fractions during vinification of Sherry wines

Changes in some polyphenol fractions after prefermentative must treatments, during alcoholic fermentation and postfermentation standing of Sherry wines were studied. The prefermentative treatments were hyperoxidation, sulphur dioxide addition or both simultaneously. In general, all the fractions increased in concentration in every type of must, possibly as a result of their extraction from the residual sludges. These residual sludges are characteristics of Sherry wine industrial vinification. Wines from non-hyperoxidized and sulphited musts had the lowest contents of all phenolic fractions.