Hybrid nano-carrier of citral in starch composites for potential application in active packaging

Nowaday the use of essential oils, having antimicrobial activity, is quite limited in the field of active packaging for the difficulty to retain the active compound for a long time into the material. The paper reports the design and fabrication of a nano-carrier able to incorporate and protect an essential oil (i.e. citral) for targeted applications. The hybrid filler was produced by growing layered double hydroxide (LDH) nanocrystals as plates on halloysite nanotubes (Hal) (Hal@LDH). Such hybrid filler was used as a carrier of citral as an antimicrobial essential oil. The active filler was incorporated into the starch matrix at 5, 10, and 15 wt% and films were produced. The structural organization of the filler was conducted by using Scansion Electron Microscopy (SEM), Thermogravimetric Analysis (TGA) and X-ray Diffraction (XRD) analysis. The obtained bio-composite films were structurally analyzed through XRD and SEM with EDX analysis. The physical performances were evaluated through the analysis of mechanical properties, contact angle, radical scavenging activity and release kinetics of citral, as a function of filler loading. To assess the possibility of using such composites for food packaging applications, tests were carried out on different strains such as Escherichia coli, Listeria monocytogenes, and Salmonella bongori.