**4. Conclusions**

PCL-SE5

PCL-SE10

PCL-SE20

 no viable counts

 no viable counts

 no viable counts

In the present study, SE solid dispersions with proven antioxidant and antimicrobial activities were successfully incorporated at different loading contents (5%, 10%, and 20%) within the PCL matrix by the electrospinning technique with the aim to develop antioxidant and antimicrobial packaging materials. The electrospun fibrous mats were post-processed by means of the annealing treatment to produce continuous, transparent, active films. The obtained results gave an insight into the effect of SE addition on the physicochemical and functional properties of the PCL-based film. Thus, the properties of the PCL-based solutions and morphology of the formulated films were affected by the SE content. Namely, thinner electrospun fibers were produced when higher SE contents were loaded. Generally, the here obtained systems presented a good contact transparency. UV-light barrier and water resistance, i.e., hydrophobicity, were generally enhanced when SE was loaded within the PCL matrix. The presence of SE had a negligible effect on thermal stability and tensile parameters of the films. On the other hand, SE led to a general decrease in barrier properties to water and D-limonene. Finally, the SE incorporation triggered remarkable DPPH*·* free radical scavenging ability and antimicrobial action against *Staphylococcus aureus* and *Escherichia coli*. As the SE content increased, the films presented more effective antiradical ability and activity against *Escherichia coli*. The evaluated characteristics of the PCL-based films containing SE sugges<sup>t</sup> that the here-developed systems are potential candidates as active materials in food packaging applications, which would delay oxidation processes and prevent microbiological contamination.

**Author Contributions:** Conceptualization was devised by V.N. and J.M.L.; methodology, validation and formal analysis were performed by A.S., C.P. and J.M.L.; investigation, resources, data curation, writing-original draft preparation, writing-review & editing were carried out by A.S., C.P., L.C., V.N. and J.M.L.; supervision: J.M.L. and C.P.; project administration: J.M.L.; funding acquisition: V.N. and J.M.L.

**Funding:** This research was funded by COST Action FP1405 (STSM reference number 39168), the EU H2020 ResUrbis project (Reference number 730349) and the Ministry of Education, Science and Technological Development (Republic of Serbia) project number III46010.

**Acknowledgments:** A.S. is a recipient of a contract from the Serbian Ministry of Education, Science and Technological Development (Project No III46010) and the STSM grant. The CSIC-UJI Joint Unit in "Polymer Technology" is also acknowledged.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
