Mass Spectrometry of Inulin Hydrolyzate Prepared Using Subcritical Water

Abstract

In order to establish the industrial production of difructose anhydride III (DFA III) from inulin using subcritical water, we investigated the effect of subcritical water phases (5 preset temperature: 150, 155, 160, 165, 170℃ , pressure: 3.0-5.0 MPa) on hydrolysis of inulin. The inulin hydrolyzate components determined by mass spectrometry were difructose anhydrides (DFAs) including DFA III, monosaccharides and oligosaccharides with degrees of polymerization (DPs) of 2-12. The DPs of oligosaccharides prepared at 165 and 170℃ were 2-4 and those at 150, 155 and 160℃ were 2-12. Hydroxymethylfurfural (HMF) and furfural were also detected in the inulin hydrolyzate by UV-Vis spectrometry. The optimum temperature for converting inulin to DFA III was temperature of 160-165℃ , pressure of 3.0-5.0 MPa. This study showed a potential of formation of DFA III from inulin under these subcritical water phases.