## 3 Results and Discussion
### Analysis of Fermented Milk, Milk-Soya, and Soya Yoghurt Products
#### 3.2.5 Selected Carbohydrates Content  
In our study, the cow's milk before fermentation contained 4.60 g of lactose per 100 g, with no detectable amounts of glucose or galactose. In comparison, the soya beverage contained sucrose (0.255 g), raffinose (0.048 g), stachyose (0.344 g), and verbascose (0.010) g/100 g; meanwhile, glucose, galactose, and maltose were not detected. The concentrations of selected carbohydrates in all yoghurt product variants are shown in Table 4. In the cow's milk yoghurt product variants, the glucose, galactose, and lactose contents were determined on all the days of storage. The other yoghurt product variants were assayed for glucose, galactose, maltose, lactose, sucrose, raffinose, stachyose, and verbascose. Samples of cow's milk yoghurt products showed the presence of significant amounts of lactose, but the lactose content did not change during cold storage of the yoghurt samples, regardless of the type of bacterial starter culture used for milk fermentation. As for glucose and galactose, their amounts were either undetectable or trace; these values did not change during the refrigerated storage of the cow's milk yoghurt product samples. Cow's milk-soya yoghurt product samples were also characterized by significant lactose contents and low or undetectable contents of the other analyzed carbohydrates. In each case, their concentrations did not change in a statistically significant way during the 21 days of refrigerated storage of the yoghurt samples. The addition of propionic bacteria to the yoghurt bacterium starter culture or the use of propionic bacteria starter culture alone for beverage fermentation did not result in significant changes in the concentrations of the analyzed carbohydrates during the cold storage of these yoghurt product samples. The situation was different for variants of soya yoghurt products stored in a refrigerator. Lactose was not found in them, and only small amounts of glucose, galactose, maltose, raffinose,and verbascose were detected. Their contents did not change during the refrigerated storage of the yoghurt samples, regardless of the type of bacterial starter culture used in their fermentation. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Type of Carbohydrate**} & **Storage Time [days]** & **0** & **7** & **14** & **21** \\ \cline{2-5}  & \multicolumn{4}{c}{**Cow’s Milk Yoghurt Products**} \\ \hline  & yoghurt bacteria fermented beverages & & & \\ glucose & nd  & nd & nd & nd \\ galactose & 0.01 a  & 0.01 a  & 0.01 a  & 0.01 a  \(\pm\) 0.01 & 0.01 a  \(\pm\) 0.01 & 0.01 a  \(\pm\) 0.01 \\ lactose & 0.44 b  & 0.03 b  \(\pm\) 0.02 & 0.40 b  \(\pm\) 0.02 & 0.42 b  \(\pm\) 0.03 \\  & yoghurt and propionic bacteria (1:1) fermented beverages & & & \\ glucose & \textless{}0.01 a  & \textless{}0.01 a  & \textless{}0.01 a  \(\pm\) 0.01 a  \\ galactose & 0.01 a  \(\pm\) 0.01 & 0.01 a  \(\pm\) 0.00 & 0.01 a  \(\pm\) 0.01 a  \(\pm\) 0.01 a  \\ lactose & 0.42 b  \(\pm\) 0.03 & 0.45 b  \(\pm\) 0.03 & 0.40 b  \(\pm\) 0.02 & 0.34 b  \(\pm\) 0.03 \\  & propionic bacteria fermented beverages & & & \\ glucose & 0.01 a  \(\pm\) 0.01 & 0.01 a  \(\pm\) 0.00 & 0.01 a  \(\pm\) 0.