## 3 Results and Discussion
### Moisture Content, Water Activity, and Particle Size D\({}_{4,3}\) Parameter of Powders  
The values of moisture content, water activity, and particle size D\({}_{4,3}\) parameter of spray-dried microcapsules formulated by adding different oils with various oil/dry mass ratios (20 and 30%) are displayed in Table 4. The moisture content of the reference sample was 4.04% \(\pm\) 0.04. For powders with 20% of oil the moisture content was in a broad range from 3.28% \(\pm\) 0.01 (milk thistle oil) to 5.95 \(\pm\) 0.02 (pumpkin oil), whereas for powders of 30% oil, the results range even broader from 2.72% \(\pm\) 0.02 (hemp oil) to 5.9% \(\pm\) 0.01 (cedar tree oil) (Table 4). Figure 4: Viability rate after spray drying as a function of the content of oil used and its relation to the melting temperature (in blue 20% and in red 30% of oil). \begin{table}
\begin{tabular}{c c c c c} \hline  & & \multicolumn{2}{c}{**Transition Temperature [\({}^{\circ}\)C]**} & \\
**Type of Oil** & **1** & **2** & **3** & **1** \\ \hline Cedar tree & \(-30.98\) & & & \(-58.64\) \\ Pumpkin & \(-30.85\) & \(-14.45\) & \(-7.64\) & \(-65.60\) \\ Borage & \(-63.70\) & \(-27.32\) & \(-9.61\) & - \\ Nigella & \(-28.03\) & & & \(-61.21\) \\ Hemp & \(-40.81\) & \(-29.91\) & & \(-63.17\) \\ Milk thistle & \(-37.55\) & \(-24.71\) & \(-3.89\) & \(-67.10\) \\ \hline \end{tabular}
\end{table} 
Table 3: Comparison of transition temperatures for melting and crystallization of different oils based on DSC measurements. The lowest water content was in the microcapsules formulated with the addition of hemp oil with a ratio of oil/dry mass of a solution of 30% (2.72% \(\pm\) 0.02) and the highest with _pumpkin oil_ in a ratio of 20% (5.95% \(\pm\) 0.02). The moisture content in all samples, both with the addition of lower (20%) and higher (30%) content of oils, significantly differs from the reference sample (\(p\) < 0.05). The samples with a 20% addition of pumpkin and borage oil, as well as cedar and hemp oil, do not differ significantly from each other (\(p\) > 0.05), while all samples with a 30% addition of oils differ significantly from each other (\(p\) < 0.05) (Table 4). [PERSON] et al. [27] spray-dried _Lacticaseibacillus casei_ 431 using the system based on whey protein isolate, gum Arabic (WPI-GA), and in whey protein isolate, tuna oil, gum Arabic (WPI-O-GA), obtained the final moisture content of the powders 2.90 \(\pm\) 0.2 and 3.19 \(\pm\) 0.2%, respectively. By adding tuna oil during the SD process, they obtained 56.19% of live bacteria, while without the addition of oil, only 37.62% [27]. According to [PERSON] et al. [46], lower water amounts (<6%) are required to prolong the shelf life of probiotic powders, which complies with the results presented in this study [7]. However, no relationship between the amount of oil added and the moisture content in the powder was observed. There was also no relationship between moisture (both using 20% and 30% oils) and viability immediately after spray drying (Table 4). The water activity (\(a_{w}\)) of the reference sample was 0.120 \(\pm\) 0.02. The \(a_{w}\) value ranges from 0.118 \(\pm\) 0.002 (hemp oil in a ratio of 30% to dry mass of solution) to 0.373 \(\pm\) 0.002 (nigella oil in a ratio of 20%). In powders with 20% oil, the results range from 0.151 \(\pm\) 0.001 (hemp oil) to 0.373 \(\pm\) 0.002 (nigella oil), whereas in powders with 30% oil they are in the range from 0.118 \(\pm\) 0.002 (hemp oil) to 0.258 \(\pm\) 0.003 for both milk thistle and borage oils. In general, when a smaller amount of pumpkin, nigella, hemp, and borage oil was used, the water activity of the powders after drying was higher than when a larger amount of these oils was applied, while an opposite relation was observed for cedar tree and milk thistle oils. The \(a_{w}\) value of powders with the addition of hemp oil, both 20% and 30%, does not differ significantly from the reference sample (\(p\) > 0.05).