## 3 Results and Discussion
### Rheological Properties of Fermented Samples  
The flow behaviors of the products were determined based on shear stress and deformation velocity values. The behavior and viscosity values of the samples at 19 rpm (with a \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Calibration Data** & **Linearity Range** & **Slope (\(\mu\)g/mL)** & **Intercept** & & & & \\
**Compounds** & **(\(\mu\)g/mL)** & **Slope (\(\mu\)g/mL)** & **(\(\mu\)g/mL)** & **r** & **LOD (\(\mu\)g/mL)** & **LOQ (\(\mu\)g/mL)** \\ \hline Vitamin A & 1.0–50 & 12,789 & 13,913 & 0.999 & 0.269 & 0.977 \\ \hline Vitamin D & 0.5–15 & 44,423 & 1567.7 & 0.999 & 0.090 & 0.300 \\ \hline Vitamin E & 0.25–7.5 & 48,611 & 54,328 & 0.999 & 0.062 & 0.208 \\ \hline Vitamin K1 & 0.15–5.0 & 23,001 & \(-\)2111 & 0.999 & 0.040 & 0.132 \\ \hline Vitamin K2 & & & & & & \\ (MK-7) & 0.02–0.5 & 111,582 & \(-\)1804.3 & 0.999 & 0.003 & 0.011 \\ \hline Lactic Acid & 500–3000 & 574.30 & \(-\)35,601 & 0.999 & 374.834 & 1249.450 \\ \hline Acetic Acid & 250–1250 & 547.01 & 5814.7 & 0.999 & 21.023 & 70.077 \\ \hline Nitric Acid & 50–300 & 1416.30 & \(-\)40,274 & 0.999 & 10.139 & 33.798 \\ \hline Formic Acid & 100–500 & 908.21 & \(-\)2836.50 & 0.999 & 18.907 & 63.023 \\ \hline Glucose & 100–2500 & 1255.40 & \(-\)60,924 & 0.999 & 25.263 & 84.543 \\ \hline Lactose & 500–7500 & 1755.30 & \(-\)79,311 & 0.999 & 76.322 & 254.407 \\ \hline Galactose & 100–1250 & 2237.50 & \(-\)252,460 & 0.999 & 12.143 & 40.477 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Calibration data of studied compounds. shear rate of 20 1/s) are shown in Figure 2A,B. The viscosity values of the products ranged from 57.11 to 116.54 mPa x s. The highest viscosity was observed in the BB-p product with the _B. bifidum_ strain followed by the LA-p product with the _L. acidophilus_ strain. This situation can be related to its production of EPS or other biopolymers, despite its low dry matter content [47; 48]. A study conducted by [PERSON] et al. [49] also showed that the _L. acidophilus_ strain used in this study is an EPS pro-ducer. On the other hand, the lowest viscosity value was recorded in the LB-p product with the _L. bulgaricus_ strain. This can be attributed to the strong acid production of L. bulgaricus, which, according to the literature, does not produce EPS. The absence of EPS may lead to reduced protein aggregation and syneresis (whey separation), ultimately lowering viscosity [40]. Also, although differences in viscosity between cultures are generally attributed to EPS production, many other properties of the produced EPS, such as its unique structure, water binding ability, etc., also affect the product. On the other hand, the LH-p (61.37 mPa s) and LC-p (81.14 mPa s) samples showed moderate viscosity levels. The _L. casei_ strain in this study is notable for its EPS production, which significantly contributes to viscosity enhancement in fermented dairy applications [50]. However, the increase in viscosity is related to the EPS structure as mentioned above. The _L. helveticus_ strain is primarily associated with proteolytic activity and flavor development, with a less pronounced effect on viscosity. _S. thermophilus_ plays a crucial role in yogurt production and displayed moderate viscosity (66.5 mPa s). Its primary function during yogurt fermentation is to rapidly reduce pH, initiating protein gelation [51]. These characteristics collectively play a vital role in the development of fermented products. In this study, the rheological properties of the samples were analyzed using the Power Law Model, due to the non-Newtonian flow behavior of the samples and the absence  
Figure 2: Rheograms of fermented samples (**A**), viscosity values of fermented samples at shear rate of 20 1/s (**B**). LA-p: was fermented with _L. acidophilus_, LB-p: was fermented with _L. bulgaricus_, LC-p: was fermented with _L. casei_, LH-p: was fermented with _L. helveticus_, BB-p: was fermented with _B. bifidum_, and ST-p: was fermented with _S. thermophilus_ (**A**).