Synthesis and characterization of novel bactericidal Cu/HPMC BNCs using chemical reduction method for food packaging

摘要

In this research copper nanoparticles (Cu NPs) were incorporated in the biodegradable hydroxypropyl methylcellulose (HPMC) matrix using the simple and low cost chemical reduction method for application as food packaging material. The properties of Cu/HPMC bionanocomposites (BNCs) were studied as a function of the CuSO4 concentration. Surface morphology of the film was investigated by scanning electron microscopy. Mechanical analysis and water vapor barrier properties of HPMC/Cu nanocomposites were analyzed. It was observed that mechanical and water vapor barrier properties of the films were improved by the concentration of CuSO4. The antibacterial activity of HPMC/Cu thin films were evaluated based on the diameter of inhibition zone in a disk diffusion test against Gram positive bacteria, ie, Streptococus A., S. epidermidis, S.aureus , B.cereus and Gram negative bacteria, ie, E. coli, E. faecalis, Salmonella, P. aeruginosa using Mueller Hinton agar at different concentration of CuSO4. The results revealed a greater bactericidal effectiveness for nanocomposite films containing 5 % of CuSO4. Packages prepared from HPMC/Cu nanocomposite films were used for meat packaging. The films were filled with meat and then stored at 4 °C. Microbial stability of the meat was evaluated after 3, 7, 10 and 15 days of storage. The results showed that microbial growth rate significantly reduced as a result of using this nanocomposite packaging material.