## 3 Results and Discussion  
### Preparation of Electrospun Pectin-Based Fibers  
The morphology of the resultant electrospun fibers is shown in Figure 1. A solution of pure pectin was initially also tested but, instead of continuous jets, it formed large droplets when subjected to high voltages during electrospinning due to the limited viscoelasticity and insufficient chain entanglements of the carbohydrate [37; 38; 39]. A similar phenomenon was faced by [PERSON] et al. [38] during the electrospinningning of pectin. In order to increase the viscoelasticity of pectin, different quantities of PEO\({}_{2000}\) from 0.1 to 1.0 wt% were added to the pectin solutions for electrospinningning, the here so-called S1 to S4. The addition of PEO can help reducing the repulsive forces among negatively charged pectin chains, enhancing chain entanglement and fiber formation [45]. The primary intention was to keep the PEO\({}_{2000}\) content at a minimum value in order to produce electrospun fibers with the highest content of pectin. In Figure 1a it can be observed that the electrospinningning of the pectin solution having 0.1 wt% PEO\({}_{2000}\), that is, S1, resulted in fibers with a discontinuous and beaded morphology. The fibers produced from S2, shown in Figure 1b, which is based on 0.25 wt% PEO\({}_{2000}\), were more continuous and non-beaded. However, the resultant electrospun mat showed poor integrity as these easily fractured during detachment from the collector. In the case of S3, made of a pectin solution with 0.5 wt% PEO\({}_{2000}\), neat fibers free of beads and with a uniform diameter were produced as it can be observed in Figure 1c. Furthermore, branched and thick pectin fibers were obtained for the electrospinningning of S4, which contained 1 wt% of PEO\({}_{2000}\) and are shown in Figure 1d. These results confirm that the use of a carrier polymer in an appropriate amount is a key parameter in order to achieve continuous and non-defected fibers during electrospinningning. Based on these results, S3 was selected due to it contained the optimal amount of PEO\({}_{2000}\) that yielded the fibers with the highest uniformity and a relatively low diameter, whereas S1, S2, and S4 were discarded from the study. Although there was not any particular requirement for the diameter, it was necessary to obtain continuous and free-bead fibers in order to produce films. Thereafter, different types and amount of plasticizers were also tested to improve the film-forming capacity of the electrospun pectin mats. Therefore, glycerol or PEG\({}_{900}\) were added to the pectin solution based on the S3 composition in which the PEO\({}_{2000}\) content was kept constant at 0.5 wt%. One can observe in Figure 1e-j that similar morphologies, based on smooth and continuous fibers but slightly thinner in the case of PEG\({}_{900}\)-containing fibers, were generated when the plasticizers were added. The average diameters of the electrospun pectin-based fibers are summarized in Table 2.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Solution**} & \multirow{2}{*}{**Viscosity (cP)**} & **Surface Tension** & **Conductivity** & **Fiber Diameter** \\  & & **(mN/m)** & **(μS-cm)** & **(nm)** \\ \hline S1 & 1892 \(\pm\) 78 1  & 28.8 \(\pm\) 0.2 1  & 7.25 \(\pm\) 0.12  & - \\ S2 & 3066 \(\pm\) 48 2  & 28.4 \(\pm\) 0.3 1  & 6.37 \(\pm\) 0.15  & 156 \(\pm\) 33 1  \\ S3 & 5950 \(\pm\) 219  & 30.3 \(\pm\) 0.2 2  & 6.10 \(\pm\) 0.10  & 186 \(\pm\) 32  \\ S4 & 12,155 \(\pm\) 1660 1  & 32.9 \(\pm\) 0.2 1  & 5.99 \(\pm\) 0.25  & 299 \(\pm\) 41  \\ S5 & 5511 \(\pm\) 299  & 31.6 \(\pm\) 0.2 1  & 5.64 \(\pm\) 0.37 [FOOTNOTE:2]Footnote 2: \(\approx\)43 [ENDFOOTFigure 1: Scanning electron microscopy (SEM) images of the electrospun mats obtained from the pectin-based solutions of: (**a**) S1; (**b**) S2; (**c**) S3; (**d**) S4; (**e**) S5; (**f**) S6; (**g**) S7; (**h**) S8; (**i**) S9; (**j**) S10.