# Encapsulation of Fennel Essential Oil in Calcium Alginate Microbeads via Electrostatic Extrusion
## 4 Conclusions  
In the present study, electrostatic extrusion emerged as a successful technique for the encapsulation of fennel EO, offering promising prospects for various applications. The incorporation of whey protein into the alginate polymeric matrix yielded favorable outcomes, enhancing the encapsulation efficiency and loading capacity. Moreover, the choice of drying method significantly impacted these parameters, with freeze-drying demonstrating superiority over air-drying. Optimal encapsulation efficiency was achieved when applying a mixture of 1.5% alginate and 0.75% whey protein, followed by freeze-drying. The sphericity and shrinkage of the beads were largely influenced by the applied carrier mixture, where adding whey protein resulted in more desirable characteristics. Air-drying led to a more pronounced reduction in bead sphericity and an increase in the microbeads' shrinkage factor compared to freeze-drying. Analysis of swelling kinetics unveiled the influential role of the carrier type, with the addition of 1.5% whey protein inducing anomalous behavior across all alginate concentrations. For formulations targeting Fickian diffusion release, adding 0.75% whey protein to 1.5 or 2% alginate emerged as a favorable option. GC-MS analysis revealed no qualitative disparities between the initial and encapsulated fennel EO. However, a decline in individual compound content was observed, with more volatile compounds exhibiting greater reductions. Despite this, the average retention of volatile compounds stood at a respectable 58.95%. Therefore, it can be concluded that electrostatic extrusion using alginate and whey protein presents a promising avenue for fennel EO encapsulation. Further investigation into the incorporation of a wider range of carrier materials and the adjustment of their concentrations is necessary to refine the encapsulation process and achieve the utmost quality in fennel EO microbeads. Nevertheless, the findings of this study underscore the potential for innovative advancements in encapsulation technology to enhance the delivery and efficacy of EOs in various applications.  
Conceptualization, M.R. and E.D.; methodology, M.R. and E.D.; formal analysis, K.R., E.C. and M.R.; investigation, K.R. and E.D.; data curation, K.R., E.D. and M.R.; writing--original draft preparation, E.D.; writing--review and editing, M.R., E.C. and I.E.G.; supervision, M.R.; project administration, V.D.-U.; funding acquisition, V.D.-U. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Croatian Science Foundation, grant number IP-01-2018-4924.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors would like to thank Ireks Aroma Ltd. for providing the fennel essential oil used for this experiment.  
The authors declare no conflicts of interest. The funders had no role in the design of this study, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results.