Production of Fructooligosaccharides by High Pressure-treated Crude Inulinase Enzymes

Abstract

We examined effects of high pressure treatment on a crude inulinase enzymes preparation to prepare fructooligosaccharides (FOS) by using fructosyltransferring activity in it. By a treatment of the crude enzyme solution at 700MPa for 60min at pH 5.0, activities degrading inulin, nystose and 1-kestose decreased to 0.9%, 2.5% and 14.7% of its original activities, respectively. But sucrose degrading activity still remained up to 51.2%, suggesting that an exo-type inulinase was almost inactivated, while β-fructofuranosidase activity was survived relatively. Fructooligosaccharides actually formed were broken down into glucose and fructose almost completely, when the non-treated crude enzyme solution was used for the reaction with 16% or 48% (w/v) sucrose at pH 5.0 and 50°C for 24 hours. Contrary to this, fructooligosaccharides were not degraded and remained, when the crude enzyme solution treated by high pressure at 700MPa for 60min was applied under the same conditions. It was suggested that these results were attributable to the inactivation of exo-type inulinase under high pressure.