Improvement of the flavour of Falanghina white wine using a purified glycosidase preparation from Aspergillus niger

Glycosidases are enzymes of particular interest for the wine-making and fruit-juice processing industry as the hydrolysis of glycoside-terpenols generates the free terpenols which contribute to the bouquet. However, the crude industrial preparations available on the market contain different types of glycosidases and contaminating enzymes whose contemporary action can produce undesired effects. This paper describes an effective and cheap procedure for purifying: and separating different glycosidases present in an industrial crude extract and their use in comparative tests for flavour improvement of Falanghina wines. The methodology, which can be scaled up to an industrial level, allows the separation of alpha-L-rhamnopyranosidase, beta-D-glucopyranosidase and alpha-L-arabinofuranosidase on partial cross-linked chitosan, with a recovery of 90, 74 and 70%, respectively. These activities were characterized for their optimal pH and temperature and stability in wine. The crude enzymatic preparation and the purified glycosidases were used and compared for the flavour improving of Falanghina white wine. (C) 2000 Elsevier Science Ltd. All rights reserved.