Abstract: A konjac glucomannan (KGM)/chitosan (CS) antimicrobial film was prepared by a sol-gel method using fulvic acid as the cross-linking agent. The physical, mechanical, structural and antimicrobial properties of the antimicrobial film was evaluated by rheology, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). Results showed that the introduction of fulvic acid promoted the formation of hydrogen bonds and electrostatic interactions between the functional groups of KGM and those of CS, thereby improving the thermostability and optical properties of the antimicrobial film. Meanwhile, compared with KGM/CS antimicrobial films, the mechanical properties of KGM/CS antimicrobial films added with fulvic acid increased by 16.85 mPa. Water vapor permeability (WVP) of KGM/CS antimicrobial films was 8.65 g/(Pa·s·m) and KGM/CS antimicrobial films added with fulvic acid was 5.25 g/(Pa·s·m). More importantly, the film had good antimicrobial properties and thus could be applied in active food packaging to maintain the quality of foods.

Key words: konjac glucomannan; chitosan; fulvic acid; antimicrobial properties; active food packaging