# Microencapsulation of Tomato
## 3 Results and Discussion
### Response Variables of Experimental Design
#### 3.3.1 Encapsulation Efficiency and Loading Capacity  
EE is a response variable of great importance in the encapsulation of bioactive compounds, since it indicates the number of bioactive compounds of the feed which, in fact, were encapsulated. According to [PERSON] et al. [30], EE is strongly affected by the drying inlet temperature and type and concentration of wall material used. EE values of tomato pomace extract with arabic gum ranged between 3.4 and 20.5% (Table 1), whereas for encapsulation with inulin was slightly higher, ranging from 6.9 to 25.3% (Table 1). These results are in the range of those reported by [PERSON] et al. [19] for microencapsulation of lycopene in modified starch by atomization in spray drying (between 21.0 and 29.7%) and by [PERSON] et al. [30] for the microencapsulation of ginger essential oil using cashew gum as the main wall material and inulin as secondary material (15.8% for the 1:3 mixture of cashew gum and inulin). For both arabic gum and inulin microparticles, a good fit of Equation 1 to EE experimental data was achieved, with a coefficient of determination (R\({}^{2}\)) of 0.91 and 0.92, respectively (Table 2). The response surfaces are presented in Figure 3a,c. As can be seen, the increase in drying temperature led generally to an increase in the EE in the entire concentration range studied for both wall materials. In the case of arabic gum, EE increased for drying temperature values up to 200 \({}^{\circ}\)C. However, with inulin, EE increased when the temperature increased from 110 to 155 \({}^{\circ}\)C, but for a further increase up to 200 \({}^{\circ}\)C, a decrease of EE was observed. This fact may be due to the effect of air inlet temperature on particle formation that depends on the wall material. High temperatures lead to a fast evaporation of water from the surface of the particle, which results in rapid formation of the surface crust. The formation of this crust protects the bioactive compound during the drying process. Though, for some materials, in the present work, inulin inlet temperatures above a specific value may cause fissures, pores, and broken particles to a larger extent, resulting in the loss of the bioactive compounds and, consequently, reducing EE [31; 32]. Regarding the effect of wall material concentration on EE, the surface responses indicated that for both inulin and arabic gum, a decrease of biopolymer concentration led to an increase in the amount of core material encapsulated. This fact may be attributed to the lower viscosity of the feed, which led to a higher water evaporation rate from the liquid droplets with consequent faster dried particles formation. LC is defined as the number of bioactive compounds, in this study expressed as lycopene, which, in fact, is within the particles produced. LC values ranged from 1.15 to 2.10 mg lycopene.g\({}^{-1}\) particles and between 0.87 and 3.08 mg lycopene.g\({}^{-1}\) particles, for arabic gum and inulin, respectively. Overall, the particles obtained with the highest lycopene content were those produced with 9.4% arabic gum at 186.8 \({}^{\circ}\)C and with 5% inulin at 155 \({}^{\circ}\)C.  
The values of LC with arabic gum were not successfully fitted to the second order model. Though, from Table 1, for both wall materials, LC tends to follow a similar trend as EE in what concerns the effect of wall material concentration and drying temperature, the latter up to 155 \({}^{\circ}\)C.  
[PERSON] et al. [33] studied the microencapsulation of black carrot using tapioca starch, arabic gum, and maltodextrin as wall material and indicated a greater loss of anthocyanins content of the particles obtained for each wall material by increasing the drying inlet temperature.Kha et al. [34] also indicated that the increase in input drying temperature and maltodextrin concentration (wall material) led to the reduction of both the LC and EE in the microencapsulation of bioactives of the gac fruit. In both works this behavior was attributed to thermal degradation and oxidation of the bioactives.