## 3 Results and Discussion
### Rheological Properties of the Obtained Fermented Whey Beverages
\begin{table}
\begin{tabular}{c c c} \hline
**Fermented Whey** & **Apparent Viscosity** & **Dynamic Viscosity [mPas \(\times\) g/cm\({}^{-3}\)]** \\
**Beverages** & **[Pa-s]**\(\pm\)**SD** & \(\pm\)**SD** \\ \hline SKKr/R & 0.21 a \(\pm\) 0.01 & 16.67 d \(\pm\) 4.71 \\ \hline SSKr/R & 0.21 ab \(\pm\) 0.00 & 3.67 ab \(\pm\) 1.16 \\ \hline SSK/R & 0.31 c \(\pm\) 0.00 & 1.17 a \(\pm\) 0.24 \\ \hline SKK/R & 0.31 c \(\pm\) 0.00 & 2.50 ab \(\pm\) 0.00 \\ \hline SSKr/DR & 0.31 c \(\pm\) 0.00 & 3.00 ab \(\pm\) 0.50 \\ \hline SSK/DR & 0.30 c \(\pm\) 0.00 & 2.00 ab \(\pm\) 0.00 \\ \hline SKKr/DR & 0.21 a \(\pm\) 0.00 & 8.50 bc \(\pm\) 3.20 \\ \hline SKK/DR & 0.30 c \(\pm\) 0.00 & 2.50 ab \(\pm\) 0.00 \\ \hline SSKr/NP & 0.23 abc \(\pm\) 0.05 & 17.66 d \(\pm\) 1.43 \\ \hline SKKr/NP & 0.30 bc \(\pm\) 0.00 & 11.67 cd \(\pm\) 1.12 \\ \hline SSK/NP & 0.93 e \(\pm\) 0.05 & 26.67 e \(\pm\) 2.00 \\ \hline SKK/NP & 0.80 d \(\pm\) 0.08 & 46.33 \(\pm\) 3.81 \\ \hline \end{tabular} a-f Statistical differences in the various columns are indicated by different letters (p < 0.05). SKKr/R—uppasteurized sour cow whey with sea buckthorn juice; SSKr/R—uppasteurized sweet cow whey with sea buckthorn juice; SSK/R—uppasteurized sweet goat whey with sea buckthorn juice; SKK/R—uppasteurized sour goat whey with sea buckthorn juice; SKK/DR—uppasteurized sour cow whey with with rosehip juice; SSK/DR—uppasteurized sweet goat whey with rosehip juice; SSK/DR—uppasteurized sweet goat whey with rosehip juice; SSK/DR—uppasteurized sweet goat whey with rosehip juice; SSK/NR—uppasteurized sweet goat whey; and SKK/NP—uppasteurized sour goat whey.  
\end{table} 
Table 2: Results of the apparent and dynamic viscosity (_p_ < 0.05) measurements of fermented whey beverages with the addition of various fruit juices at laboratory scale. SKKr/R (16.67 mPas\(\cdot\)g/cm\({}^{3}\)), indicating that sea buckthorn juice might contribute more to the thickening of the beverage than rosehip juice. Increases in viscosity may be due to the solids and oil present in the sea buckthorn juice [22; 33], which have a higher viscosity than rosehip juice [34], hence a higher viscosity of the whole beverage. These findings are in line with other research on the rheological properties of fermented dairy products. In the literature, these findings are in accordance with those for the rheological properties of fermented dairy products. Its use has already been tested by [PERSON] et al. [35], where a higher concentration of collagen increased the viscosity and this resulted in higher bioavailability. Also, whey beverages fortified with hydrolyzed collagen modified its viscosity significantly in a dose-dependent manner too. This is in agreement with the results observed in our study, where similar improvements of rheological properties were accomplished upon the addition of fruit juices, and function ingredients other than collagen and fruit juice are able to markedly manipulate the rheological characteristic of fermented beverages. [PERSON] et al. [36] demonstrated that the viscosity and stability of whey-based drinks (more with higher concentrations of the byproduct) were significantly enhanced with oligofructose. Additionally, [PERSON] et al. [37] studied the influence of hydrocolloids on the texture and structure of yoghurt-type products. They reported that modified starches increase the viscosity and also enhanced the stability of dairy beverages. Moreover, the addition of the physically modified starch (PMS) offered an improved mouthfeel, smoothness, and viscous nature of the product. Such findings indicated the PMS gives potential rheological and sensory enhancers to fermented whey beverages. [PERSON] et al. [13] compared fermented beverages from goat and cow milk in relation to their physicochemical and sensory attributes. The data obtained using a statistical analysis indicated that the beverages prepared from goat's milk showed higher viscosity and stability parameters compared to those elaborated with cow's milk.