Improving the physical and protective functions of semolina films by embedding a blend nanofillers (ZnO-nr and nano-kaolin)

Abstract

© 2017 Elsevier Ltd Regarding the reduction of synthetic food packaging materials’ pollution, the purpose of the present study is to examine a new biopolymer-based film to be employed in food packaging. Diverse ratios (1:4, 2:3, 3:2, and 4:1 w/w) of ZnO nanorod (ZnO-nr) and nano-kaolin combinations were incorporated into semolina film matrices, and nanocomposite films were formed using the solvent casting method. We examined the resultant films in terms of their barrier, optical, heat sealability, and structural attributes. Whilst increasing the level of ZnO-nr resulted in the decline of the oxygen permeability (OP) of the films, the increase in the percentage of nano-kaolin led to the improvement in the heat sealability of such films. Moreover, the intensification of the nanoparticle loading triggered a decline in the moisture content and water solubility of the nanocomposite films at all different nanofiller ratios. The increase of the ZnO-nr content also significantly affected the light absorbance level of the semolina films. Remarkable differences in the surface morphology were observed between the control and bio-nanocomposite films as revealed by the FESEM images. The semolina-based bioactive films exhibited distinctive antimicrobial activity against gram-negative food pathogens, namely Escherichia coli. Succinctly, regarding food packaging purposes, the findings of this study advocate the direct incorporation of ZnO-nr and nano-kaolin into semolina matrices to produce active biodegradable films.