## 3 Results and Discussion
### Water Content, Water Activity, and Hygroscopicity of Insect Powders
of protein and fat), determined in our previous study [45]. A smaller amount of assayed protein for the IR-CD-dried powder indicates a greater amount of denatured protein, and this promotes water adsorption. Nevertheless, practically, this is a beneficial phenomenon, as the lower hygroscopicity ensures better stability of the powder during storage. Among the powders tested in our study, the one obtained by the IR-CD method will likely maintain better stability during storage, provided that the relevant environmental temperature and humidity conditions will be applied. Both the water activity and water content of the obtained powders immediately after the drying process were low (Table 1), which indicates their microbiological safety and the stability of chemical and physical properties (described in Section 3.1). However, it should be considered that the powders may come into contact with the ambient air during their storage, packaging, and trade. In such situations, sorption properties become crucial from the safety point of view. Sorption properties characterize the product's ability to adsorb or desorption water from the surrounding environment. The sorption properties of food products are mainly determined by the chemical composition and their physical properties and can also be shaped by technological processes [46; 47; 48]. Sorption properties can be studied using static, equilibrium methods, which lead to obtaining the dependence of water activity on water content called the sorption isotherm. A detailed analysis of the isotherm course allows, among other things, the determination of the capacity of the monolayer. \begin{table}
\begin{tabular}{c c c c} \hline
**Treatment** & **Water Content** & **Water Activity** & **Hygroscopicity After 72 h** \\
**(g H\({}_{2}\)O/g d.m.)** & **(–)** & **(g H\({}_{2}\)O/100 g d.m.)** \\ \hline CD & 0.048 a 1 \(\pm\) 0.005 & 0.177 a \(\pm\) 0.009 & 41.13 a \(\pm\) 1.76 \\ IR–CD & 0.137 b \(\pm\) 0.014 & 0.246 b \(\pm\) 0.009 & 50.95 b \(\pm\) 0.79 \\ \hline \end{tabular}
\end{table} 
Table 1: The water content, water activity, and hygroscopicity of black soldier fly powders processed by convective (CD) and infrared convective (IR–CD) drying methods. [PERSON] et al. [47] investigated the sorption isotherms of lesser mealworm (_Alphatibus diperines_) and house cricket (_Acheta domesticus_) powders, observing that both exhibited a sigmoidal curve characteristic of type II according to the [PERSON] et al. [49] classification. Using the BET (Brunauer-Emmett-Teller) equation, they determined the monolayer capacity of 3.59 g water/100 g d.m. for lesser mealworm and 3.25 g water/100 g d.m. for house cricket powders. Their analysis of isotherm components suggested that variations in hygroscopic properties were primarily influenced by the chemical composition of the powders [47]. [PERSON] et al. [50] reported similar findings while examining the sorption behavior of dried and ground house cricket (_Acheta domesticus_) and black soldier fly larvae (_Hermetia illucens_) using the static method. Likewise, [PERSON] et al. [51] assessed the sorption isotherms of processed lesser mealworm larvae (_Alphatibus diaperinus_) in different forms, including whole powder, protein concentrate, and textured protein. Their results were interpreted using the GAB (Guggenheim-Anderson-de Boer) model, classifying the obtained isotherms as type III according to the classification of [PERSON] et al. [49]. An alternative approach to studying sorption properties is the dynamic method, which enables the determination of the water diffusion coefficient and equilibrium moisture content--the final moisture level a material reaches after prolonged storage in a given environment [32].