Coatings of xylan/chitosan complexes reinforced with micro/nanocellulose for food packaging applications

Polyelectrolyte complexes (PECs) of Xylan (Xyl) and Chitosan (Ch) were investigated as coating materials to enhance paper properties for food packaging applications. These complexes were blended with different contents of micro/nanofibrillated cellulose (M/NFC) (5-20 wt% of total dry coating weight) to explore potential synergistic effects. The rheological strength and gel properties of the resulting Xyl/Ch PEC-M/NFC formulations were assessed. Coated papers underwent comprehensive analyses, including examinations of morphology, oxygen and water vapor barrier properties, mechanical strength, and printing characteristics. The addition of M/NFC resulted in increased shear viscosity and yield stress of the coating formulations. Additionally, it enhanced the surface wettability of the coated papers, leading to higher contact angles when measured with water and castor oil. Xyl/Ch PEC coated paper exhibited a drastic reduction in Gurley air permeability and development of enhanced barrier properties compared to the base paper. On the other hand, the printing properties, including gamut area, gamut volume and optical density of the Xyl/Ch PEC coated papers, were superior to those of papers coated only with starch. These results demonstrate the promising potential of Xyl/Ch PEC-M/NFC coating formulations for enhancing paper properties and their suitability for food packaging applications.