Pre-fermentative replacement of sulphur dioxide by lysozyme and oenological tannins: Effect on the formation and evolution of volatile compounds during the bottle storage of white wines

In this work, the effects on the volatile profile of the pre-fermentative substitution of SO₂ with lysozyme and oenological tannins were studied in white wines. At the same time, in order to understand the changes of volatile compounds in SO₂-free wines, the evolution of volatiles was evaluated over 1 year of storage in bottles. For this purpose, a number of laboratory scale fermentations of SauvignonBlanc musts were carried out and the effects of three variables (SO₂, lysozyme and oenological tannins) were investigated by means of GC–MS analysis. Results showed that the replacement of SO₂ with lysozyme and oenological tannins influenced the volatile composition of wines at the end of the alcoholic fermentation. Wines fermented with SO₂ showed higher total alcohol amounts, while the presence of oenological tannins augmented the level of esters. The presence of SO₂ influenced also the alcohols and esters profiles of wines during bottle storage. Moreover, the presence of oenological tannins displayed a positive role in maintaining the amounts of esters over certain levels in wine stored for 1 year, likely due to their oxygen scavenging ability. By contrast, acids were less affected by the investigated adjuvants both at the end of the alcoholic fermentation and during the storage time.