Chitosan Solution Containing Zein and Essential Oil as Bio Based Coating on Packaging Paper

Urška Vrabič Brodnjak,Katarina Tihole

doi:10.3390/coatings10050497

Abstract

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 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 the 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 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.

Highlights

Packaging paper plays an important role in many industrial sectors
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 data of the water vapour permeability (WVP) showed that the addition of the rosemary oil to the coating solutions had a good effect on the water and the oil barrier properties

Summary

Introduction

Packaging paper plays an important role in many industrial sectors. New technologies for food packaging have come forth, including active packaging among the most promising innovations. It consists in incorporating active compounds into the packaging material, which are useful for food protection as well as in terms of antioxidant and/or antimicrobial activity. The availability on the market and great properties such as non-toxicity, gas, aroma and grease barriers make it possible to use these materials in many applications [7]. Polysaccharides have low hydrophilicity and limited use in materials where water vapour barriers are of the utmost importance [8,9]

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