## 3 Results and Discussion
### Performance of Spray-Dried Powder  
The spray-dried samples redispersed in water had a larger mean droplet size of emulsion before spray-drying. This phenomenon denoted that some of the nanoparticles formed aggregations during the spray-drying process. Similar studies on the change of particle size during drying have shown that the particle size of essential oils encapsulated in zein nanoparticle samples also increased after \begin{table}
\begin{tabular}{c c c c} \hline
**Treatments (*)** & **Droplet Size (nm)** & **Polydispersity Index** & **Zeta Potential (mV)** \\ \hline F1 emulsion-chi 0.0\% & 243.6 \(\pm\) 18.3 bed & 0.239 \(\pm\) 0.020 bed & \(-\)16.4 \(\pm\) 1.1 c \\ F1 emulsion-chi 0.067\% & 224.4 \(\pm\) 10.5 cd & 0.202 \(\pm\) 0.009 d & 20.5 \(\pm\) 0.3 ab \\ F1 emulsion-chi 0.2\% & 288.7 \(\pm\) 5.2 bc & 0.213 \(\pm\) 0.006 cd & 24.8 \(\pm\) 2.8 a \\ F1 emulsion-chi 0.33\% & 311.5 \(\pm\) 4.9 b & 0.204 \(\pm\) 0.016 cd & 24.9 \(\pm\) 2.9 a \\ F2 emulsion-chi 0.0\% & 200.5 \(\pm\) 12.7 d & 0.264 \(\pm\) 0.013 bc & \(-\)10.5 \(\pm\) 4.2 c \\ F2 emulsion-chi 0.067\% & 417.4 \(\pm\) 61.3 a & 0.486 \(\pm\) 0.042 a & 14.4 \(\pm\) 5.4 b \\ F2 emulsion-chi 0.2\% & 301.1 \(\pm\) 24.5 b & 0.250 \(\pm\) 0.024 bed & 19.1 \(\pm\) 5.5 ab \\ F2 emulsion-chi 0.33\% & 286.9 \(\pm\) 15.0 bc & 0.299 \(\pm\) 0.020 b & 15.9 \(\pm\) 1.3 ab \\ \hline \end{tabular}
\end{table} 
Table 2: Droplet size, polydispersity index, and zeta potential of emulsions. lyophilizing [30]. Increased particle size was probably caused by the imperfections of the hydration or the occurrence of structural changes within atomized droplets during spray-drying. From the research by [PERSON] et al. [23], structural changes can occur due to the differences in the distribution of essential oils that evaporated and condensed during spray-drying which later cooled. The difference in the concentration of eugenol used in the F1 and F2 treatment samples perhaps caused differences in the particles' structural changes during drying. Therefore, F1 samples (2.0% eugenol) had a larger dispersed particle size than that of the F2 samples (1.0% eugenol). Moreover, increasing the chitosan concentration also increased the size of the dried particles. The chitosan content of 0.33% in the emulsion significantly increased the size of the spray-dried powder particles. The F1 powder-chi 0.33% had the largest particle size (1243 nm), as well as PdI value (0.71) (Table 3). In contrast to the emulsions, the F1 spray-dried samples had smaller zeta potential values than that of the F2 spray-dried samples. However, the trend remained the same, where F1-chi 1.0% had a higher zeta potential value than that of the F1-chi 0.2% and F1-chi 0.067%, likewise for the F2 samples. Encapsulation performance of eugenol using WPMD conjugates and chitosan was determined by the percentage of encapsulation efficiency (EE) and loading capacity (LC). The percentage of EE and LC increased with increasing levels of chitosan concentration of 0.067%, 0.2%, and 0.33% (Table 4). Chitosan content of 0.33% in formula F1 significantly increased the LC and EE, however, formula F2 showed a different phenomenon. This finding is similar to that of [PERSON] et al. [31], who concluded that coriander essential oil-loaded microspheres prepared in an alginate/chitosan system with a 1:2 ratio had a higher value of entrapment efficiency than microspheres prepared in an alginate/chitosan system with a 1:1 ratio. The F1 spray-dried sample with 0.33% chitosan solution (F1 powder-chi 0.33%) had the highest loading capacity and was significantly different from the other samples (Table 4). The spray-dried samples with 0.067% chitosan solution for both formulas F1 and F2 showed the lowest percentage of EE and LC. These values were lower than the EE and LC of formulas F1 and F2 without chitosan. This could be attributed to the instability of the emulsion and the droplet size. [PERSON] et al. [23] stated