Characterization and sustained release study of starch-based films loaded with carvacrol: A promising UV-shielding and bioactive nanocomposite film

Present study was aimed to develop sustainable active films with starch/carvacrol for potential food packaging. The physicochemical, antioxidant, antibacterial and release kinetics were analyzed. The results demonstrated that carvacrol nanoemulsion (CNE) was uniformly dispersed in the film matrix and interacted with hydrogen bonds. The addition of carvacrol improved the thermal stability, UV shielding, water solubility and water vapor permeability of the films, but reduced their mechanical properties. Films prepared with CNE (≥10%) exhibited high antioxidant activity (>60%), and inhibition zones of the best antimicrobial activities achieved 28.6 ± 1.4 and 57.2 ± 3.7 (mm) against E. coli and S. aureus. The release kinetics of carvacrol from the nanocomposite films exhibited a higher carvacrol release in the acidic simulant than in the aqueous simulant at equilibrium. The dominant mechanism of carvacrol release was Fickian diffusion and showed minimal erosion. Overall, the sustainable composite films exhibited desirable physical properties and bioactivity, and could be used as edible materials for food preservation, especially for extending the shelf life of acidic foods.