## 3 Results and Discussion
### Moisture Content, Water Activity, and Particle Size D\({}_{4,3}\) Parameter of Powders
The water activity of the powder with the addition of 20% cedar tree oil also does not differ significantly from the control sample (\(p\) > 0.05). In the case of other powders with lower (20%) and higher (30%) oil content, significant differences in \(a_{w}\) values are observed (\(p\) < 0.05). Higher water activity values have been observed to correlate with better viability when using cedar tree, nigella, hemp, and milk thistle oil, for both oil contents. When using pumpkin and borage oil, the relationship is reversed (a higher percentage of live _Lbs. rhamns_ corresponds to lower \(a_{w}\)), however, in the case of forage oil, the difference in viability is relatively small, maybe due to already high viability rate of bacterial cells for systems with addition of this oil. [PERSON] and [PERSON] spray-dried fresh cultures of _Bifidobacterium breve_ R070 (BB R070) and _Bifidobacterium longum_ R023 (BL R023) using milk fat and/or denatured whey proteins as immobilizing material. The water activity and moisture content of the obtained powders \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Type of Oil** & \multicolumn{2}{c}{**Water Content**} & \multicolumn{2}{c}{\(a_{w}\)} & \multicolumn{2}{c}{**D\({}_{43}\) [um] of Powders**} \\ \hline  & 20\% \({}^{*}\) & 30\% \({}^{*}\) & 20\% \({}^{*}\) & 30\% \({}^{*}\) & 20\% \({}^{*}\) & 30\% \({}^{*}\) \\ Reference sample & 4.04 \(\pm\) 0.035 \({}^{*}\) & 0.120 \(\pm\) 0.02 \({}^{*}\) & 29.4 \(\pm\) 2.1 \({}^{*}\) & \\ Pumpkin & 5.95 \(\pm\) 0.017 \({}^{b}\) & 5.8 \(\pm\) 0.026 \({}^{b}\) & 0.277 \(\pm\) 0.003 \({}^{b}\) & 0.225 \(\pm\) 0.002 \({}^{b}\) & 415.7 \(\pm\) 2.8 \({}^{b}\) \({}^{c}\) & 463.8 \(\pm\) 0.8 \({}^{b}\) \\ Cedar tree & 4.7 \(\pm\) 0.026 \({}^{c}\) & 5.9 \(\pm\) 0.010 \({}^{c}\) & 0.181 \(\pm\) 0.002 \({}^{a}\) & 0.224 \(\pm\) 0.003 \({}^{b}\) & 433.2 \(\pm\) 3.3 \({}^{c}\) & 724.5 \(\pm\) 2.5 \({}^{c}\) \\ Nigella & 5.35 \(\pm\) 0.010 \({}^{d}\) & 5.56 \(\pm\) 0.017 \({}^{d}\) & 0.373 \(\pm\) 0.002 \({}^{c}\) & 0.128 \(\pm\) 0.001 \({}^{c}\) & 175.9 \(\pm\) 2.6 \({}^{d}\) & 321.1 \(\pm\) 1.9 \({}^{d}\) \\ Hemp & 4.82 \(\pm\) 0.010 \({}^{c}\) & 2.72 \(\pm\) 0.017 \({}^{e}\) & 0.151 \(\pm\) 0.001 \({}^{a}\) & 0.118 \(\pm\) 0.002 \({}^{a}\) & 396.2 \(\pm\) 5.2 \({}^{e}\) & 498.8 \(\pm\) 1.4 \({}^{e}\) \\ Borage & 5.9 \(\pm\) 0.017 \({}^{b}\) & 5.41 \(\pm\) 0.020 \({}^{f}\) & 0.335 \(\pm\) 0.002 \({}^{c}\) & 0.258 \(\pm\) 0.003 \({}^{d}\) & 222.8 \(\pm\) 7.5 \({}^{f}\) & 321.5 \(\pm\) 1.9 \({}^{d}\) \\ Milk thistle & 3.28 \(\pm\) 0.010 \({}^{e}\) & 5.49 \(\pm\) 0.026 \({}^{e}\) & 0.230 \(\pm\) 0.01 \({}^{d}\) & 0.258 \(\pm\) 0.001 \({}^{d}\) & 54.6 \(\pm\) 2.7 \({}^{e}\) & 506.8 \(\pm\) 2.0 \({}^{f}\) \\ \hline  & & & & & \\ \end{tabular} \({}^{*}\) Values are mean \(\pm\) standard deviations of triplicate determinations. \({}^{*}\) a ratio of oils to dry mass of starting dispersion. Values with different lowercase letters in the same column are significantly different at \(p\) < 0.05. The statistical analyses were performed using Statistica version 10 StatSoft Poland, (Krakow, Poland).  
\end{table} 
Table 4: Water content, water activity \(a_{w}\), and particle size parameter D\({}_{4,3}\) of spray-dried powder. were at an acceptable level for food powders. The same \(a_{w}\) value was obtained for BB R070 with both encapsulation systems, and for BL R023 with added milk fat and denatured whey proteins (0.16). For BL R023 with added milk fat, the water activity value was 0.18. The moisture content for _Bifidobacterium breve_ R070 was 1.95 and 1.40, and for _Bifidobacterium longum_ R023 it was 2.05 and 2.05. These results were obtained for powders with added both milk fat, and milk fat and denatured whey protein, respectively [11]. [PERSON] et al. [27] found out for microencapsulated _L.