Rheological and anti-microbial study of silica and silver nanoparticles-reinforced k-carrageenan/hydroxyethyl cellulose composites for food packaging applications

Abstract

Sustainable food packaging films were developed using a combination of k-Carrageenan (k-C), hydroxyl ethyl cellulose (HEC), silicon dioxide (SiO2), and silver (Ag) nanoparticles. The CH-SiO2/Ag nanocomposites showed promising results, mainly due to their transparency, flexibility, low cost, and environmental friendliness. The structure and uniform morphology of the CH-SiO2/Ag nanocomposites were determined by FT-IR, XRD, and SEM analysis. Barrier properties (water vapor permeability-WVP), thermal properties (T5% loss, char yield), and mechanical properties determined for the k-C/HEC and k-C/HEC-SiO2/Ag nanocomposites, which improved by 3.3–1.9 × 10−9 gm/m2 Pa s (WVP), 59.1–115.7 °C (T5%), 13.4–29.3% (char yield), 23.8–41.5 MPa (tensile strength), and 22.3–28.9 (EB), respectively. The contact angle of the k-C/HEC-SiO2/Ag nanocomposites were in the range of 60.1°–76.4°. The UV transmittance of the k-C/HEC composites decreased with the addition of SiO2 and Ag nanoparticles. However, the transparency of the composites was not affected, and it inhibited UVA and UVB rays by the addition of Ag nanoparticles. The viscosity of the k-C/HEC composites increased with the SiO2 content and decreased with the shear rate. All the composites exhibited shear-thinning behavior. The storage modulus of the prepared composites is higher than the loss modulus in the entire frequency region. Overall, SiO2 and Ag nanoparticles improved the hydrophobic nature of the k-C/HEC-SiO2/Ag films and showed significant activity against six common food pathogens, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Bacillus subtilis, Salmonella typhi, and Cronobacter sakazakii. The synergistic combination of k-C/HEC-SiO2/Ag nanocomposite has potential candidate for packaging and other biomedical applications.