A mixture of purified glycosidases from Aspergillus niger for oenological application immobilised by inclusion in chitosan gels

Several glycosidases (β-D-glucopyranosidase, α-L-arabinofuranosidase, α-L-rhamnopyranosidase), purified from an Aspergillus niger enzyme preparation were immobilised contemporarily with a method in view of its possible application in the wine-making and fruit-juice processing industry. Immobilisation of the three enzymes was carried out by inclusion using chitosan gels and subsequent cross-linking with glutaraldehyde. This was followed by addition of various agents in order to improve the gel’s physical and mechanical properties, reduce enzyme release phenomena and increase immobilisation yields and operational stability. The best additives proved is be gelatine and silica gel, of which a more in-depth study was made. Finally, the immobilised glycosidases were used to increase the aroma in a model wine solution.