Sensitivity to humidity can lead to spontaneous, rapid and uncontrolled decomposition of the material (5, 12). The physicochemical properties of the obtained PuOC/Zein-based bilayer film, moisture content, total soluble matter and swelling, during four weeks of storage, are presented in Figure 2. A slight decrease in the content of humidity (Figure 2a) during the storage time. The percentage of total soluble matter decreased after the first week and then remained stable during the storage period (Figure 2b). The swelling percentage also decreased during the storage period and after four weeks was three times lower than the initial week (Figure 2c). These results show that during the storage period at ambient conditions, the PuOC/Zein-based films likely lose moisture and lead to the formation of new bonds and cross-linking. Figure