Effect of enzymatic aroma release on the volatile compounds of white wines presenting different aroma potentials

Wines from Maria Gomes (Fernao Pires) and Bical varieties were treated with an enzymatic preparation, Lallzyme de Lalvin, with beta-glucosidase, pectinase, arabinosidase and rhamnosidase activity. The reference and enzyme-treated wines were submitted to a process of continuous liquid-liquid extraction with dichloromethane and analysed by GC-MS. The volatile contents of the wines were 199 and 188 mg 1(-1), respectively, for Maria Gomes and Bical. Both varieties contained aliphatic and aromatic alcohols, terpenoids, esters, aliphatic acids and lactones. Enzymatically treated wines showed an increase of 9% in the total amount of volatile compounds of Maria Gomes, due, mainly, to the increase of geraniol (67%), terpendiols (96%), phenols and aromatic alcohols (26%) and esters (32%). Some of them were within their perception limits and may have a contribution to the floral and fruity notes. Conversely, no significant modifications were introduced by enzymatic treatment in the total amount of volatile compounds of Bical wine. The presence of aromatic alcohols in significant amounts, which may represent an interesting characteristic in Bical wines, was not increased by the treatment used. This study with two white varieties grown in the same Appellation shows that the effectiveness of aroma release by enzymatic treatment, using a broad range of enzymatic activities, is closely dependent on the varietal aroma potential, knowledge of which is a key determinant for full exploitation of wine qualities. (C) 2004 Society of Chemical Industry.