Development and evaluation of chitosan based active nanocomposite films containing bacterial cellulose nanocrystals and silver nanoparticles

Abstract

Bacterial cellulose pellicles synthesized by Gluconacetobacter xylinus in the molasses medium were acid hydrolyzed to obtain cellulose nanocrystals. The isolated bacterial cellulose nanocrystals (BCNC) and silver nanoparticles (AgNPs) were used to prepare chitosan (Ch) based nanocomposite films. It was found that the incorporation of BCNC and AgNPs into chitosan films significantly influenced apparent color and transparency of the films. In addition, sensibility to water, water vapor permeability and mechanical properties were greatly improved after formation of nanocomposite. The formation of hydrogen bonds between chitosan and BCNC was detected by FTIR analysis. XRD studies confirmed the appearance of crystalline peaks in the nanocomposite films. The results of DSC showed significant effect of nanocrystals and nanoparticles on thermal stability. FE-SEM micrographs showed that BCNC and AgNPs which dispersed homogenously in chitosan matrix, had an average size of 20-30 and 35-50 nm, respectively. The Ch/AgNPs nanocomposite film exhibited strong antibacterial activity against food borne pathogens. Results of this study suggested that nanocomposite films containing BCNC and AgNPs can be used as an active food packaging material for increasing shelf life of packaged foods.