## 3 Results and Discussion
### Fourier Transform Infrared Spectroscopy (FTIR)  
The eugenol spray-dried powder of formula F1 with different levels of chitosan concentrations had similar spectra profiles (Figure 2A). The presence of eugenol and the formation of encapsulation could be detected from the appearance of peaks at wavenumbers in the range of 1517-1561 cm\({}^{-1}\) in the F1 spray-dried powder samples. The encapsulation process caused a shift in wavenumbers of the spray-dried powder sample, however, the wavenumbers were in the range of functional groups that represent C = C aromatic ring and secondary amines, NH bend. This wavenumbers' shift probably indicated physical interactions among eugenol, WPMD, and chitosan. The results of Piletti [43] explained that the physical interaction between eugenol with the \(\beta\)-cyclodextrinrin molecules caused the modification of the O-H functional group. The IR bands of eugenol, WPMD conjugates, and chitosan are presented in Table S1. The existence of a functional group in the sample could also be shown by the percentage of transmittance. In general, the percentage of transmittance in the wavenumber range of 1550-1650 cm\({}^{-1}\) for F1-chi 0.0% was lower than for F1-chi 0.067% and F1-chi 0.33%. This proved that F1-chi 0.33% had more chitosan than other F1 samples.  
The existence of a C = C aromatic group in all F1 powder samples was seen from peaks in the 1508 cm\({}^{-1}\) region. These results are in line with those of [PERSON] et al. [44] and [PERSON] and [PERSON] [33]. Strong absorption was detected in F1 powder-chi 0.33%, indicating the higher eugenol content (Table S2). The data in Table 2 show that the F1 powder-chi 0.33% had the highest percentage loading capacity of eugenol. This was also reinforced by the detection of the OH bend at 1408-1411 cm\({}^{-1}\) and a C-H aromatic ring at 559-998 cm\({}^{-1}\). The wavenumber range of 1400-1419 cm\({}^{-1}\) represents phenol and OH bend groups [45]. The intensity of these peaks in F1 powder-chi 0.33% was slightly higher than in F1 powder-chi 0.0%, 0.067%, and 0.2% (Figure 2A). The peak shifts that occurred were also likely related to the physical interaction between eugenol and the wall materials in the encapsulation process as explained above.  
The profiles of FTIR spectra of F2 spray-dried powder samples were generally different from F1 powders (Figure 2B). Compared with the spectra of F1 powders, the percentage of transmittance of spectra of F2 powders was higher, meaning that the absorption was lower, which indicates the weak intensity of certain functional groups (Table S3). Peaks in the range of 3271-3295 cm\({}^{-1}\) experienced an increase in transmittance. This indicated the intensity of the hydrogen bonds between eugenol and the WPMD conjugate or between eugenol and free maltodextrin in F2 powders was lower than in F1 powders. Peaks in the range of 1563-1577 cm\({}^{-1}\) in a spray-dried powder containing chitosan represented NH functional groups that showed the presence of chitosan. The existence of eugenol was detected at peaks of 1401-1402 cm\({}^{-1}\), which could have been shifted from specific wavenumbers of eugenol (Table S1). However, the intensity of these wavenumbers was lower than that of F1 powders,  
Figure 2: Infrared spectra of F1 (**A**) and F2 (**B**) spray-dried powders.  
as seen from the percentage of the transmittance (Figure 2A,B). This was because the eugenol loading of F2 powders was lower than that of F1 powders (Table 4).