Physicochemical properties of degraded konjac glucomannan prepared by laser assisted with hydrogen peroxide.

The exploration of methods for degrading konjac glucomannan (KGM) is of great significant and technological interest. Here, laser at the power of 10 W was employed to degrade KGM. The laser degraded konjac glucomannan (LDK) was analyzed by viscosity, Rheology, Differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy and laser light scatter (LLS). The viscosity of the LDK decreased from 8.38 Pa·s to 2.26 Pa·s and the average molecular weight (Mw) decreased from 7.6 × 10⁵ Da to 5.7 × 10⁵ Da with a polydispersity index (PDI) of 1.166. FT-IR spectra and IR images of the LDK indicated that the breakage of glucosidic bonds occurred during laser irradiation. DSC results indicated that the thermal stability of KGM has improved slightly after degradation. In addition, the determination of 1,1-diphenyl-2-picrylhrazyl (DPPH) radical scavenging activity suggested that the antioxidant activity of the LDK improved versus KGM. This stratagem provides a new pathway for efficiently degrading KGM.