Development of Chitosan-Based Active Films with Medicinal Plant Extracts for Potential Food Packaging Applications

Abstract

In this study, 2% chitosan (Ch) (w/v) was enriched with 1% Lippia javanica, Syzygium cordatum, and Ximenia caffra extract to form Ch+L, Ch+S, and Ch+X, respectively. The control film was the chitosan (Ch) film without plant extracts. The composite films were assessed for their antifungal ability using the agar diffusion method against economically relevant plant pathogens, Botrytis cinerea, and Penicillium expansum. These chitosan films were further evaluated using an X-ray diffractometer and scanning electron microscope, and their physical and mechanical properties were also assessed. The medicinal plants in the chitosan matrix had the highest inhibition zone (10 mm) against P. expansum, while the chitosan-only films had the lowest inhibition zone (3.3 mm). Notably, Ch+S and Ch+X films had the highest inhibition zone (10 mm) against B. cinerea, while chitosan-only films did not avert the spread of B. cinerea. Ch+L films had the highest film thickness (0.189 mm), density (1.62 g·cm3), swelling degree (48.6%), and water solubility (32.8%). Films with other plant extracts had moderate properties, while chitosan without plant extract had the least film thickness (0.128 mm), density (1.08 g·cm3), swelling degree (31.9%), and water solubility (18.9%). X-ray diffraction images revealed that the chitosan films fused with plant extracts altered the extent of crystallinity of the films because they ranged between 14,710.43 for chitosan-only films and 26,288.31 a.u. for Ch+S films. Enriching the chitosan-based films with the investigated medicinal plant extracts resulted in different favorable properties and could make good candidates for food preservation and packaging if optimized.