Physical properties and antibacterial activity of quaternized chitosan/carboxymethyl cellulose blend films

Antibacterial property of packaging is needed to improve the microbiological safety of foods. The aim of this work was to incorporate various amounts of carboxymethyl cellulose (CMC) into films based on quatemized chitosan (2-N-Hydroxypropyl-3-trimethylammonium chloride chitosan, HTCC) to develop coating for preserving food. The HTCC film and blend films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, scanning electron microscopy, and thermogravimetric analysis. The effects of CMC content on the physical properties and antibacterial activities of the blend films were investigated. The effect of coating bananas with the films on their preservation was also determined. The results revealed that HTCC and CMC in the blend films interacted by hydrogen bonding. Both of them could be partly miscible. Compared with HTCC100 film, CMC incorporation improved tensile strength, thermostability, and water resistance, however, increased oxygen permeability, and decreased light transmittance and antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Bananas coated with the HTCC/CMC blend films had longer shelf life than uncoated bananas. CMC incorporation thus evidently reinforced the HTCC film and lowered its WVP. These results suggest that HTCC/CMC blend films can be used as food packaging materials. (C) 2015 Elsevier Ltd. All rights reserved.