Preparation and characterization of deacetylated konjac glucomannan / pectin composite films crosslinked with calcium hydroxide

Deacetylated konjac glucomannan (DKGM)/calcium pectin (Ca-PEC) composite films were prepared by calcium hydroxide to realize deacetylation of konjac glucomannan (KGM) and the crosslinking of pectin at the same time. Fourier transform infrared spectroscopy (FTIR) indicates that there are intermolecular hydrogen bond and crosslinking structure between DKGM and Ca-PEC. The physical properties of the composite films are characterized by mechanical properties, water vapor permeability (WVP), swelling degree (SD), water solubility (WS), thermogravimetry (TG) and Opacity. The results exhibit that deacetylation of KGM and crosslinking structure of pectin reduce the swelling degree and water solubility of the films, as well as improve its thermal stability and tensile strength. These are attributed to enhanced intermolecular interactions, more compact entanglement of molecular chains and more solid spatial network structures. When pectin content is 40%, the combination property of DKGM / Ca-PEC composite film is the best.