Hydrolysis kinetics of trisaccharides consisting of glucose, galactose, and fructose residues in subcritical water

The hydrolysis kinetics of trisaccharides consisting of glucose, galactose, and fructose residues with different glycosidic bonds, 1-kestose, D-melezitose, D-raffinose, and lactosucrose, in subcritical water were conducted over the temperature range of 150-230 °C and at a constant pressure of 10 MPa. The hydrolysis of trisaccharides in subcritical water proceeded consecutively, i.e., one cleavage of the two bonds antedated the other. The preceding cleavage was not expressed by the first-order kinetics, but by the kinetics considering the concentration of the acidic compounds, which were produced by the degradation of the constituent monosaccharides. The hydrolysis of the constituent disaccharides, except sucrose composed of the α-Glc-(1→2)-β-Fru bond, obeyed first-order kinetics. All of the rate constants of the hydrolytic kinetics were determined, and the values were found to depend on the type of bond.