Effect of nanoclay on physicochemical and barrier properties of kefiran biopolymer films

Biodegradable films and coatings are developed to improve quality and to extend shelf-life of food products. In the present research, physicochemical and barrier characteristics of nano-biopolymer films composed of kefiran-montmorillonite (MMT; 0, 1, 3 and 5 % w/w) were studied. Results showed that the thickness, chromaticity parameters b (yellow–blue) and the total color difference (∆E) increased by increasing the nanoclay content, whereas, the moisture content, water absorption, water solubility, water vapor permeability, chromaticity parameters a (red–green) and whiteness index (WI) decreased by increasing it. Also, the nanoparticles had no significant effect on transparency and lightness parameter (L) of films. Study the mechanical properties showed that nanoclay increases the tensile strength of films whereas, its effect on the elongation at break is different in various concentrations, so that this factor increase until concentration of 3% of the nanoclay and decrease in higher concentrations (5%).