Bio Based Paper Coatings Containing Protein, Polysaccharide and Essential Oil

Modifications of the packaging paper surface play an important role in a variety of industries, especially in the food sector. In general, packaging paper can be exposed to many external environmental influences such as humidity, temperature, stress, forces, pressure and chemical impacts, etc. Therefore, modifications of the paper surface play an important role in a variety of industries. Namely, unmodified paper has poor water and oil resistance due to its porous structure. In the 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 layers; the 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 chitosan-rosemary oil coating solution. The result of this two-layer coating showed excellent water (Cobb60 value of 2.18 g/m2) and oil barrier properties. All coated papers showed high thermal stability, especially those coated with chitosan, zein and rosemary oil as layer-by-layer. Scanning electron microscopy was used to verify the surface differences of the coated papers, such as closed structure, pores and smoother surface, especially in layer-wise coated samples. Due to the good mechanical and chemical properties, coated papers with rosemary oil can be used in many applications, possibly also in the field of repellents. In the future, the effect of the analysed dual coating against insect infestation will be analysed.