Kappa-carrageenan based active nanocomposite films incorporated with nanohalloysite and niosome-encapsulated Lippia citriodora essential oil: Preparation and characterization

This research aimed to fabricate and investigate the Kappa-carrageenan (KC) based films incorporated with Lippia citriodora essential oil-loaded niosomes (NEO) and nanohalloysite (HNT). Different levels of L. citriodora essential oil (LCEO) niosomes (0, 5 and 10 % w/w) and HNT (0, 3 and 6 % w/w) were added to the KC matrix. The physicochemical, morphological and functional properties of prepared films were assessed. The average size, polydispersity index and Zeta potential of niosomes were ∼145 nm, 0.19 and -21.7 mV, respectively. The FT-IR, FE-SEM and XRD results confirmed the proper compatibility of polymer and loaded nano-additives. It was found that the incorporation of NEO and HNT had increasing and decreasing effect on the WVP of films, respectively. The tensile strength and elongation at break decreased to 7.1 MPa and 2.7 %, respectively, by increasing LCEO content. By adding 6 % HNT, the thermal decomposition temperature of films increased from 259.5 °C to 261.7 °C. In contrast, incorporating NEO reduced the heat resistance of the films to 252.9 °C. The microstructure analysis showed a heterogeneous structure of KC film and good dispersion of NEO and HNT in the matrix. The results suggested that the KC NEO film had good antioxidant activity (DPPH scavenging potential of ∼54 %) and was more effective against Staphylococcus aureus (inhibition zone of ∼12 mm) than KC NEO HNT films. The antioxidant and antimicrobial activity of the films containing NEO increased by increasing the LCEO concentration. Generally, the fabricated nanocomposite active KC film containing nano-niosome and nano-halloysite indicated an appropriate potential for using as active food packaging.