Insights into the evolution of certain sulfur-containing compounds during artificial ageing of Xinomavro PDO wines

Complex reactions favouring production or retention of volatile sulfur compounds (VSCs) are crucial for the development of red wine ageing bouquet. This study aimed to investigate the development of certain VSCs in Xinomavro red wines and examine the influence of grape origin on wine composition as it aged. Wines from Amyndeon and Naoussa PDO zones underwent artificial ageing for 24 days, and thiol precursors, varietal thiols, S-methyl-l-methionine (SMM), and dimethyl sulfide (DMS) were analysed periodically. Vineyard location and duration of ageing showed great influence on the analytes measured, with interactions revealed for thiol precursors but not 3-sulfanylhexan-1-ol. Changes in SMM and DMS concentrations indicated for the first time that a DMS pro-precursor may exist in bottled Xinomavro wine, with SMM acting as a degradation intermediate. Principal component analysis grouped regional Xinomavro wines according to the chemical transformations determined during bottle ageing.