## 3 Results and Discussion
### Mechanical Characteristics of Biopolymer Films
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & \begin{tabular}{c} **Tensile Strength** \\ **(MPa)** \\ \end{tabular} & \
\begin{tabular}{c} **Elongation at Break** \\ **\"Breaking Strain\" (\%)** \\ \end{tabular} &
\begin{tabular}{c} **Toughness** \\ **(MJ)/m3** \\ \end{tabular} \\ \hline Control & 0.986 \(\pm\) 0.005 c & 139.72 \(\pm\) 1.80 b & 0.480 \(\pm\) 0.006 c \\ O-5 & 1.093 \(\pm\) 0.009 b & 143.16 \(\pm\) 1.19 b & 0.566 \(\pm\) 0.008 b \\ O-10 & 1.110 \(\pm\) 0.007 ab & 156.62 \(\pm\) 2.29 a & 0.588 \(\pm\) 0.003 ab \\ O-30 & 1.130 \(\pm\) 0.008 a & 162.21 \(\pm\) 2.53 a & 0.611 \(\pm\) 0.008 a \\ \hline \hline \end{tabular} Data are the mean \(\pm\) standard deviation (\(n=3\)). Different letters within the same column show the significant differences between the samples (\(p<0.05\)). Control: biopolymer film from non-ozonated FFS; O-5: biopolymer film from ozone-treated FFS for 5 min; O-10: biopolymer film from ozone-treated FFS for 10 min; O-30: biopolymer film from ozone-treated FFS for 30 min.  
\end{table} 
Table 5: Mechanical characteristics of biopolymer films produced from the ozone-treated film-forming solutions. The elongation at break of the samples was between 139.72 and 162.21%. The data show that the ozone treatment of the FFSs for 10 and 30 min produced biopolymer films with higher elongation at break values compared to the control and O-5. The extended ozone treatment time significantly improved the flexibility of the biopolymer films. The more prolonged ozone treatment likely promoted the formation of additional intermolecular interactions and cross-linking within the film matrix. These interactions can enhance the film's structural integrity and flexibility, allowing it to stretch further before breaking. The longer treatment time may have also led to some chain scission or rearrangement, resulting in a more elastic film. The obtained values for elongation at break in this study were significantly higher than those in films from WPC observed by [PERSON] et al. [58; 59] (around 50 and 43%, respectively). In addition to the ozone treatment's effect on elongation at break, when gelatine is used with glycerol in composite film formulations, it may serve as a \"co-plasticizer\", increasing the flexibility and reducing the fragility of the films [57]. The toughness of a material is a mechanical property that describes its ability to absorb energy without fracturing. It is a measure of the material's resistance to crack propagation and is often used to characterise materials that undergo significant deformation before failure [60]. The toughness of the biopolymer films increased with increasing ozone treatment time. The control sample had the lowest toughness value (0.480 MJ/m\({}^{3}\)), while the O-30 sample (ozonated for 30 min) had the highest toughness value (0.611 MJ/m\({}^{3}\)). The formation of cross-links between polymer chains can enhance the resulting film's mechanical strength, rigidity, and toughness. Therefore, the observed increase in toughness with longer ozone treatment durations aligns with increased cross-linking expectations. A higher value of toughness indicates a film that can absorb more energy before it breaks, providing better protection for the food product. Proteins were found to have an important role in the strength and flexibility of films because they engage with surrounding molecules via various types of linkages, generating films with strength, cohesion, and viscoelasticity [61]. Overall, the results indicate that treating film-forming solutions with ozone positively impacts the mechanical properties of biopolymer films. The films showed higher tensile strength, improved flexibility (higher elongation at break), and increased toughness as the ozone exposure time increased. The improved mechanical properties have the potential to create more durable and flexible biopolymer films that can be used in a variety of food and packaging industries.