*2.3. Coating Application*

The chitin suspension was applied as received while the polyphenols powder was dissolved in water. Both coatings were applied by the spray technique with a hand sprayer on one side of the paper tissue. Different amounts of ChNFs (1 wt%, 7.5 wt%) and polyphenols (0.1 wt%, 1 wt%, 10 wt%), with respect to the tissue weight, were applied on the substrate. In addition to the tissues treated with active molecules, a reference sample treated with pure water was prepared. The same amount (30 mL) of water was used in all samples. In order to apply uniformly the coating, the application was performed at 10 cm from the surface of the tissue, equally dividing the spray between 9 application points as reported in Figure 1.

**Figure 1.** Application points selected for spray coating.
