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 fru it-juice processing industry as the hydrolysis of glycoside-terpenols gener ates 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 produ ce undesired effects. This paper describes an effective and cheap procedure for purifying: and separating different glycosidases present in an industr ial crude extract and their use in comparative tests for flavour improvemen t of Falanghina wines. The methodology, which can be scaled up to an indust rial level, allows the separation of alpha-L-rhamnopyranosidase, beta-D-glu copyranosidase and alpha-L-arabinofuranosidase on partial cross-linked chit osan, with a recovery of 90, 74 and 70%, respectively. These activities wer e characterized for their optimal pH and temperature and stability in wine. The crude enzymatic preparation and the purified glycosidases were used an d compared for the flavour improving of Falanghina white wine. (C) 2000 Els evier Science Ltd. All rights reserved.