Pectinex Ultra SP-L, a food-grade enzymatic preparation with high transfructosylating activity, was covalently immobilized on chitosan beads. The highest immobilization yield (95.9%) was obtained using 4.0% glutaraldehyde for 60 min and 80rpm at 2 5 ± 1 CC. The immobilized biocatalyst showed good operational stability, being able to retain, after the third cycle of reuse, no less than 100.0 and 73.9% of starting hydrolytic and transfructosylating activities, respectively. Results of residual activity experiments allowed estimating, for irreversible them al inactivation of both free and immobilized enzyme, the activation energy (E*d = 234.3 and 242.2kj-mol-1), enthalpy (234.4 < ΔH*d < 234.2 kj-mol-1 and 239.4 <ΔH*d < 239.3 kj-mol-1), entropy (381.2 < ΔS*d < 379.8J-mol-1. K-1 and 390.4 < ΔS*d < 389.7 J-mol-1) and Gibbs free energy (109.3 < ΔG*d < 103.9 kj-mol-1 and 111.3 < ΔG*d < 103.6 kJ-mol). The use of the immobilized enzyme in a packed bed reactor allowed obtaining, after 100 min, a fructooligosaccharide mixture containing more than 25 gL-1 1-kestose. [ABSTRACT FROM AUTHOR]