*3.7. Biodegradability*

The biodegradability of the films was studied by soil burial degradation test for 10 days. The weight loss of zein-based films was about 50–60% (Table 3), which is a clear reflection of the biodegradation process performed by the microorganisms and moisture present in the soil. Moreover, at the end of the biodegradability test, the films were thin and appeared disrupt (Figure 5b) when compared to the initial samples (Figure 5a). The FTIR spectra of the films after the soil burial degradation test (Figure 2c) showed peaks absorption and decrease in intensities as biodegradation took place, as other authors also reported [25]. These results clearly show the biodegradable nature of the zein-based films now developed.

**Figure 5.** Biodegradability: soil burial degradation test of the films. Film without EO — polystyrene Petri dishes (1), film without EO — lotus negative template (2), film with EO —polystyrene Petri dishes (3), and film with EO —lotus negative template (4); initial films at 0 days (**a**), and films after soil burial degradation test (10 days) (**b**).
