Chitosan solution containing zein and essential oil as bio based coating on packaging paper

Modifications of the packaging paper surface play an important role in a variety of industries, especially in the food sector. Uncoated paper has poor water and oil barrier properties due to its porous structure. In this study, packaging paper was successfully coated with six different coating solutions containing combinations of chitosan, zein and rosemary essential oil. The chitosan and zein were actually coated in two layersthe mixed chitosan–rosemary oil and the mixed zein–rosemary oil were each applied as one layer to the paper. The results showed increased oil barrier properties in the papers coated with mixed zein–rosemary oil and reduced water permeability in the papers coated with the chitosan–rosemary oil coating solution. The result of this two-layer coating showed excellent water (Cobb60 value of 2.18 g/m$^2$) and oil barrier properties. All the coated papers showed a high thermal stability, especially those coated with chitosan, zein and rosemary oil layer by layer. Scanning electron microscopy was used to verify the surface differences of the coated papers, such as the closed structure, pores and smoother surface, especially in the layer-wise coated samples. Due to their good mechanical and chemical properties, coated papers with rosemary oil can be used in many applications, possibly also in the field of repellents