## 3 Results
### Release Test  
The samples produced were compared for the release of active ingredients at room temperature (25 \({}^{\circ}\)C). Such tests were performed by the complete immersion of samples in ethanol 10% (\(v/v\)) as a food simulant. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**SCG Extract\%**} & \multicolumn{2}{c}{**ELECTROSPINNING**} & \multicolumn{2}{c}{**SOLVENT CASTING**} & \multicolumn{2}{c}{**SPIN COATING**} \\ \cline{2-7}  & **Thickness (\(\upmu\)m)** & **Specific Weight** & **Thickness (\(\upmu\)m)** & **Specific Weight** & **Thickness (\(\upmu\)m)** & **Specific Weight** \\  & & **(g/m\({}^{2}\))** & & **(g/m\({}^{2}\))** & & **(g/m\({}^{2}\))** \\ \hline
0\% & 54.0 \(\pm\) 7.52 & 33.37 \(\pm\) 0.63 & 51.23 \(\pm\) 9.47 & 73.23 \(\pm\) 1.51 & 55.80 \(\pm\) 3.24 & 61.22 \(\pm\) 0.96 \\
15\% & 35.8 \(\pm\) 2.95 & 35.12 \(\pm\) 10.6 & 37.27 \(\pm\) 7.28 & 76.34 \(\pm\) 6.38 & 53.50 \(\pm\) 3.11 & 62.86 \(\pm\) 2.89 \\
20\% & 27.4 \(\pm\) 6.43 & 26.50 \(\pm\) 3.89 & 37.93 \(\pm\) 9.49 & 80.62 \(\pm\) 1.03 & 54.25 \(\pm\) 2.98 & 63.26 \(\pm\) 2.50 \\
35\% & 31.2 \(\pm\) 4.44 & 23.92 \(\pm\) 4.33 & 43.57 \(\pm\) 11.47 & 93.29 \(\pm\) 0.92 & 50.75 \(\pm\) 1.50 & 46.24 \(\pm\) 1.04 \\
45\% & 14.4 \(\pm\) 3.36 & 19.47 \(\pm\) 3.30 & 50.80 \(\pm\) 11.48 & 66.96 \(\pm\) 5.08 & 51.28 \(\pm\) 3.33 & 46.29 \(\pm\) 0.56 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Thickness and specific weight of the zein samples produced by electrospinning, solvent casting, and spin coating by varying the SCG extract concentration. Figure 4: SEM images, at the same magnification (\(\times\)2000), of electrospun zein fibers loaded with (a) 15%, (b) 20%, (c) 35%, (d) 45% SCG extract. Figure 5a shows the caffeine migration from the polymer obtained by casting to the liquid medium over time, reported as mg of migrated caffeine per kg of polymer. In the 48 h of test, a continuous incremental release can be observed, which tended to a plateau not reached during the experimental time. The amount of caffeine released in a fixed time was strongly dependent on the extract loaded into the polymeric film. Figure 5b reports the radical ABTS\({}^{\bullet+}\) inhibition exerted by aliquots of the food simulant sampled over time, which showed antiradical power due to the extract release. As a general observation, the higher was the extract loading, the higher was the ability to scavenge the radical in a fixed time. Moreover, at the lowest extract loadings (15 and 20%, \(w/w\)), the inhibition values remained as constant up to 6 h, while significant increase was observed after 24 h. Conversely, at the highest extract loadings (35 and 45%, \(w/w\)), in 2 h was recorded a significant increase in the inhibition action, which maintains a constant value in the following observed time. The antiradical power determined by the ABTS assay was not related to the caffeine concentration, whose antioxidant activity cannot be detected by the employed colorimetric method but to the other antioxidant compounds,  
Figure 5: Results of the release tests on films obtained by solvent casting in ethanol 10% (\(p/v\)), in terms of: (**a**) caffeine released per kg of film, (**b**) radical ABTS\({}^{\bullet+}\) inhibition, and (**c**) linear correlation between the caffeine concentration released and radical inhibition power of the extract migrated into the food simulant. Different symbols indicate statistically significant differences among values over time (\(p<0.05\)) of the dataset with the same extract loading. mainly polyphenols and melanoidins [38; 39]. Figure 5c shows that a linear correlation (R\({}^{2}\) = 0.9123) can be found between the caffeine concentration released and the inhibition power, demonstrating that caffeine can be used as a marker for the entire extract behavior for what concerns the migration into the selected simulant. Films obtained by spin coating showed a faster caffeine release than casted packaging, especially in the first hours of release.