## 3 Results and Discussion
### Physical Properties of Freeze-Dried Edible Insects Larvae
#### 3.2.3 Color of Freeze-Dried Edible Insects Larvae  
The L*, a*, b* color parameters, and total color difference (\(\Delta\)E) between fresh and freeze-dried edible insects are presented in Table 3. The changes in the color parameters were dependent on the insect species and pretreatment application. The L*, a*, b* color parameters for fresh _H. illucens_ larvae were 39.4 \(\pm\) 0.8, 7.9 \(\pm\) 0.8, and 24.0 \(\pm\) 0.2, respectively, while for _T. molitor_ larvae they were 39.9 \(\pm\) 1.7, 3.1 \(\pm\) 0.2, and 17.1 \(\pm\) 1.0, respectively. The lightness (L*) of freeze-dried insects ranged from 34.7 to 42.1 and from 33.5 to 34.3 for _H. illucens_ and _T. molitor_ larvae, respectively. The utilization of PEF prior to drying affected the color parameters of the freeze-dried material. For _H. illucens_ larvae, the lightness was significantly lower than for untreated dried insects, while for _T. molitor_ larvae treated by PEF at an energy intake of 20 kJ/kg, the L* value was slightly higher. The higher L* value can be explained by irreversible electroporation and a greater number of pores, which may promote the transfer of fat globules to the surface of insect tissue [36]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Sample**} & \multicolumn{1}{c}{**L* [ –]**} & **a* [ –]** & **b* [ –]** & **\(\Delta\)E[ –]** \\ \hline \multirow{4}{*}{_H. illucens_} & Fresh & 39.4 \(\pm\) 0.8 b,* & 7.9 \(\pm\) 0.8 c & 24.0 \(\pm\) 0.2 c & - \\ \cline{2-6}  & 0 kJ/kg & 42.1 \(\pm\) 1.3 c & 5.6 \(\pm\) 0.3 b & 17.8 \(\pm\) 0.7 b & 7.3 \\ \cline{2-6}  & 5 kJ/kg & 34.9 \(\pm\) 2.2 a & 4.8 \(\pm\) 0.4 a & 15.1 \(\pm\) 1.1 a & 10.6 \\ \cline{2-6}  & 20 kJ/kg & 34.7 \(\pm\) 1.0 a & 4.5 \(\pm\) 0.3 a & 14.9 \(\pm\) 0.7 a & 10.8 \\ \hline \multirow{4}{*}{_T. molitor_} & Fresh & 39.9 \(\pm\) 1.7 b & 3.1 \(\pm\) 0.2 a & 17.1 \(\pm\) 1.0 a & - \\ \cline{2-6}  & 0 kJ/kg & 33.8 \(\pm\) 0.8 a & 10.8 \(\pm\) 0.5 c & 20.7 \(\pm\) 0.6 c & 10.5 \\ \cline{2-6}  & 5 kJ/kg & 33.5 \(\pm\) 0.6 a & 9.7 \(\pm\) 0.3 b & 19.4 \(\pm\) 0.5 b & 9.5 \\ \cline{2-6}  & 20 kJ/kg & 34.3 \(\pm\) 0.3 a & 9.4 \(\pm\) 0.3 b & 18.9 \(\pm\) 0.4 b & 8.6 \\ \hline \hline \end{tabular}  
* The same letters in columns (lowercase for _H. illucens_ larvae, uppercase for _T. molitor_ larvae) denote the same homogeneous groups, which do not differ statistically (_p_ < 0.05).  
\end{table} 
Table 3: The color parameters (L*, a*, b*), and total color difference (\(\Delta\)E, in comparison to raw material) of fresh and freeze-dried untreated (0 kJ/kg) and PEF-treated (5 and 20 kJ/kg) _H. illucens_ and _T. molitor_ larvae. Figure 2: Hygroscopic kinetics of freeze-dried untreated (0 kJ/kg) and PEF-treated (5 and 20 kJ/kg) (**a**) _H. illucens_ and (**b**) _T. molitor_ larvae. Furthermore, this may also be related to the measurement procedure, which is based on measuring the reflected beams of light from the sample surface. Dried edible insects have a lower moisture content, so light was reflected differently from the dry and porous surface, and therefore these samples are probably characterized by a higher lightness [56]. In turn, for _H. illucens_ larvae, a lower lightness during measurement may be associated with the greater porosity of the dried material and higher light retention inside its tissue [41]. The dried insects were characterized by an a* color parameter from 4.5 to 5.6 (_H. illucens_ larvae) and from 9.4 to 10.8 (_T. molitor_ larvae). Regardless of insect species, increasing the PEF specific energy intake significantly decreased the a* values. In turn, the values of the b* color parameter of the dried insects ranged from 14.9 to 17.8 and from 18.9 to 20.7 for _H. illucens_ and _T. molitor_ larvae, respectively. It was observed that the a* and b* color parameter values for the PEF-treated and freeze-dried materials were significantly lower than for the intact, dried material. Furthermore, _H. illucens_ larvae have demonstrated lower b* values and higher a* values in comparison to _T. molitor_ larvae.