## 3 Results and Discussion
### Differential Scanning Calorimetry  
All spray-dried powders containing chitosan, except the microcapsule of F2 powder-chi 0.067%, showed endothermic processes of temperature peak at 74.8 \({}^{\circ}\)C until 78.6 \({}^{\circ}\)C (Figure 1A,B). Chitosan had two endothermic peaks at 85.88 and 275.26 \({}^{\circ}\)C (Figure S2). The endothermic peak for eugenol is 258.81 \({}^{\circ}\)C [35]. The disappearance of the peaks located at these temperatures indicated that there was an interaction between the WPMD conjugates and eugenol, as well as with chitosan. Previous studies reported that the individual characteristics of the graph polymer wall material and the active compounds are not visible in the DSC graphs if the interaction and encapsulation efficiency are good [36; 37; 38]. The interaction between core and the wall material determined the retention of the active compound. According to [PERSON] et al. [39], the varied ratio of essential oil to the wall material resulted in the differences in the interaction of essential with the wall material which, then, influenced the encapsulation efficiency.  
According to the thermograms, the spray-dried powders with 0.067%, 0.2%, and 0.33% chitosan concentrations for both eugenol concentrations (F1 and F2) appeared to have adjacent endothermic peak temperatures (Figure 1A,B). Therefore, the chitosan concentration did not have a different effect on the thermal behavior of the eugenol spray-dried powder. However, the addition of chitosan as the second layer in eugenol encapsulation can protect the sample from denaturation and decomposition. This was indicated by the absence of the exothermic peak and only one endothermic peak with temperatures below 100 \({}^{\circ}\)C. The endothermic peak in the range of 100 \({}^{\circ}\)C can be related to the gelatinization process. There was a decomposition of carbohydrates and similar structures in the presence of water during heating. This process was complex because, at the same time, water vaporization also occurred. Meanwhile, the endothermic peak in the range of 200 \({}^{\circ}\)C is related to the melting materials and the possibility of partial and liquid evaporation [40].  
The thermograms showed that the formulations without chitosan (F1 powder-chi 0.0% and F2 powder-chi 0.0%) had endothermic and exothermic peak temperatures. The F1 powder-chi 0.0% had 85.75 and 189.97 \({}^{\circ}\)C endothermic and exothermic peaks, respectively. The temperature peaks of F2 powder-chi 0.0% at 81.49 and 180.61 \({}^{\circ}\)C, respectively, were lower than those of F1 powder-chi 0.0%. These two types of peak temperatures were also observed in the thermograms of the WPMD conjugate powder and the F2 powder-chi 0.067% at 70.14 and 213.09 \({}^{\circ}\)C and at 80.32 and 178.62 \({}^{\circ}\)C, respectively. The exothermic peak was attributed to the occurrence of decomposition.  
According to [PERSON] et al. [41] and [PERSON] et al. [42], the material reorganization during the spray-drying process could affect the changes in microcapsule melting temperatures. In their investigation, reorganization occurred when the polymer was heated above its transition glass temperature (Tg). In this study, the spray-drying process was held at 150 \({}^{\circ}\)C. The DSC measurements showed that the temperature of Tg maltodextrin and chitosan was not detected, while the Tg temperature of whey protein was 119.47 \({}^{\circ}\)C (Figure not shown). Therefore, the occurrence of material reorganization in eugenol encapsulation cannot be ascertained.  
Figure 1: Differential scanning calorimetry (DSC) thermogram of F1 (**A**) and F2 (**B**) spray-dried powders.