The multi-layer film system improved the release and retention properties of cinnamon essential oil and its application as coating in inhibition to penicillium expansion of apple fruit

The aim of this research is to develop, characterize and utilize a multi-layer antibacterial film using chitosan (CS) and sodium alginate (SA) as biopolymers and cinnamon essential oil (CEO) as main antibacterial ingredients. The dense cross-section of SA layer in the scanning electron microscopy (SEM) analysis verified that layer-by-layer method improved physical and mechanical properties of CS-CEO single layer film. The thermogravimetric (TGA) and fourier transform infrared (FT-IR) analysis indicated that the layer-by-layer method changed the intermolecular interaction and the thermal stability. Importantly, the multi-layer film exhibited more sustained release and higher retention rate of CEO compared CS-CEO single layer film. The multi-layer coating showed a more significant and lasting inhibition of penicillium expansion which further demonstrated that the layer-by-layer method improved the release and retention of CEO in the multiphased system. To summarize, the multilayer film system is a promising controllable release system for loading essential oils.