Preparation, characterization and mechanical properties of K-carrageenan/SiO2 nanocomposite films for antimicrobial food packaging

Abstract

Kappa-Carrageenan (KCG) films have been formulated as a packaging material. This study has been conducted to investigate the effect of incorporating SiO2 nanoparticles inside the KC Gmatrix, with the aim of enhancing the mechanical and antimicrobial properties of KCG for reinforcement purposes. Films were prepared by solution casting technique with 1.0, 3.0 and 5.0 wt% of SiO2 nano-filler content taking neat KCG as the reference for the study. Structural characterizations of the prepared nanocomposite films were carried out by Fourier transform infrared, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. SEM and TEM showed homogeneous dispersion of SiO2 nanoparticles in the KCG matrix. The tensile strength increased significantly by introducing the SiO2 nanoparticles into the KCG matrix, in which KCG/SiO2 films have greater tensile strength (53.9 MPa) when compared to the KCG polymer (46.8 MPa). The moisture uptake (MU) of nanocomposites decreased when SiO2 was introduced into the polymer matrix. The barrier property of the prepared KCG-based nanocomposite films decreased oxygen transmission rate with loading of different wt% of SiO2. SiO2 nanoparticle-loaded films produced higher zones of inhibition against Staphylococcus aureus and Escherichia coli strains compared to polymer film. This study was intended to find the applications for KCG films containing SiO2 nanoparticles to enhance the shelf-life of foods in the form of biodegradable wrapper.