Enzymatic preparations containing b-glucanases are usefully utilised in wine making to facilitate the filtration of musts and wines coming from grapes affected by Botrytis cinerea, and to induce the release of mannoproteins and oligosaccharides from the cell wall of yeast. The aim of the present work was to investigate the possible inhibitory effect of some components of wine, and in particular of ethanol, on b-glucanase activities. For this purpose, the kinetic activity of a commercial enzymatic preparation containing b-glucanases was tested utilising both model solutions (buffer solution having a pH value similar to a must/wine added or not with 13% v/v of ethanol) and a red wine. When ethanol was added to the model solution, both the kinetic constant k and glucose production suffered an about 50% decrease compared to the values detected in the absence of ethanol. A further loss of activity (about 87%) was found using red wine as reaction medium suggesting, as already reported in literature, that phenols could add their inhibitory effect to that of ethanol. Results obtained can provide some useful suggestions to be adopted during wine making. To promote the hydrolysis of the possible excess of b-glucan coming from grapes affected by Botritis cinerea, it would be more convenient to add b-glucanases before a significant amount of ethanol accumulates in the must/wine, while it is not possible to avoid the negative impact of ethanol or other possible inhibitors (phenols) to promote yeast degradation in wine left on lees.
|Autori:||Zinnai A.; Venturi F.; Quartacci M.; Andreotti A.; Andrich G.|
|Titolo:||The kinetic effect of some wine components on the enzymatic hydrolysis of beta-glucan|
|Anno del prodotto:||2010|
|Appare nelle tipologie:||1.1 Articolo in rivista|