Chitosan-Based Active Films Enriched with Moroccan Essential Oils for Antimicrobial Packaging Applications

Ensuring the microbiological safety and extended shelf-life of food products remains a global priority. In this context, the development of biodegradable and bioactive packaging films represents a promising eco-innovative solution. This study aimed to develop and evaluate active packaging films based on chitosan extracted from shrimp shells and enriched with essential oils. Chitosan was selected for its intrinsic film-forming and antimicrobial properties, while essential oils from Thymus satureioides and Rosmarinus officinalis were incorporated for their bioactivity. The extracted chitosan (EXT) showed a yield of 12%, with a degree of deacetylation sufficient for effective film formation. SEM (Scanning Electron Microscopy) analysis revealed distinct morphological differences between extracted and commercial chitosan (COM). EXT displayed a rough, highly porous surface with thin, irregularly shaped flakes and layered structures, suggesting high surface area and potential reactivity. In contrast, COM exhibited smoother, denser, and more compact platelet-like structures with fewer visible pores, indicative of higher purity and crystallinity. Antimicrobial testing of the resulting films using agar diffusion against Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis, and Escherichia coli demonstrated significantly greater inhibition zones (p < 0.05) for films enriched with essential oils compared to control films. Notably, antimicrobial efficacy increased with oil concentration, and Gram-positive bacteria were more susceptible, especially in films enriched with Thymus satureioides oil at 7.5% v/v. Overall, the study supports the potential of extracted chitosan-based films as sustainable, bioactive materials for food and pharmaceutical packaging, combining structural integrity with enhanced antimicrobial performance.