Chitosan-based edible coatings with silver-modified SiO2 nanoparticles and cinnamon essential oil (Cinnamomum burmannii) to extend shelf life of strawberry (Fragaria × ananassa)

This study evaluates the use of SiO2 nanoparticles modified with silver (Ag) and cinnamon essential oil in chitosan-based edible coatings to extend the shelf life of strawberries. The objectives were to synthesize and characterize SiO2, SiO2–Ag, SiO2@Cinn, and SiO2–Ag@Cinn nanomaterials, evaluate their antibacterial activity, and analyze the effectiveness of the coatings on strawberries. The synthesis of SiO2 was carried out using the Stöber method via hydrolysis and condensation. Silver impregnation into SiO2 was performed via a solvothermal method at 120 °C, while incorporation of cinnamon essential oil was carried out with Tween 80 as a surfactant. The edible coating solution containing the nanomaterials was partly formulated into films for transparency and thickness testing and partly applied to strawberries by dipping. The results showed that the synthesized SiO2 was amorphous, with a spherical morphology and an average size of 255.15 nm. The impregnation of silver significantly improved antibacterial activity compared to unmodified SiO2, and the incorporation of cinnamon essential oil provided further improvement. Among all formulations, SiO2–Ag@Cinn showed the strongest antibacterial activity. Our preliminary results also suggest that morphology-driven properties play a crucial role in enhancing both antibacterial and photocatalytic performance. Furthermore, the incorporation of nanofillers improved the overall performance of chitosan-based films by enhancing thermal stability and modifying barrier properties. These results indicate that nanofiller addition can effectively influence the functional characteristics of films without significantly altering their fundamental thermal behavior, thus showing significant potential to extend the shelf life of strawberries.