## 3 Results and Discussion
### Organic Acid Profiles of Fermented Samples
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{6}{c}{**(C) Vitamin A, D, E, K1, and K2 Contents of the Fermented Samples** (\(\mu\)g/mL)} \\ \hline
**Femented Samples** & **Vitamin A** & **Vitamin D** & **Vitamin E** & **Vitamin K1** & **Vitamin K2** \\ \hline \({}^{*}\)LA-p & 31.083 \(\pm\) 0.041 \({}^{\text{ax}}\) & 3.723 \(\pm\) 0.043 \({}^{\text{e}}\) & 1.009 \(\pm\) 0.006 \({}^{\text{b}}\) & 0.232 \(\pm\) 0.002 \({}^{\text{d}}\) & 0.070 \(\pm\) 0.008 \({}^{\text{a}}\) \\ LB-p & 16.326 \(\pm\) 0.013 \({}^{\text{d}}\) & 5.070 \(\pm\) 0.012 \({}^{\text{c}}\) & 0.949 \(\pm\) 0.002 \({}^{\text{c}}\) & 0.704 \(\pm\) 0.009 \({}^{\text{b}}\) & 0.030 \(\pm\) 0.003 \({}^{\text{c}}\) \\ LC-p & 23.893 \(\pm\) 0.009 \({}^{\text{b}}\) & 7.073 \(\pm\) 0.044 \({}^{\text{a}}\) & 1.087 \(\pm\) 0.005 \({}^{\text{b}}\) & 0.803 \(\pm\) 0.006 \({}^{\text{a}}\) & 0.014 \(\pm\) 0.006 \({}^{\text{d}}\) \\ LH-p & 16.549 \(\pm\) 0.054 \({}^{\text{d}}\) & 3.854 \(\pm\) 0.008 \({}^{\text{e}}\) & 0.976 \(\pm\) 0.002 \({}^{\text{c}}\) & 0.644 \(\pm\) 0.011 \({}^{\text{c}}\) & 0.048 \(\pm\) 0.001 \({}^{\text{b}}\) \\ BB-p & 20.119 \(\pm\) 0.014 \({}^{\text{c}}\) & 4.667 \(\pm\) 0.102 \({}^{\text{d}}\) & 1.135 \(\pm\) 0.004 \({}^{\text{a}}\) & 0.805 \(\pm\) 0.015 \({}^{\text{a}}\) & 0.028 \(\pm\) 0.006 \({}^{\text{c}}\) \\ ST-p & 13.253 \(\pm\) 0.066 \({}^{\text{e}}\) & 6.448 \(\pm\) 0.017 \({}^{\text{b}}\) & 0.972 \(\pm\) 0.007 \({}^{\text{c}}\) & 0.869 \(\pm\) 0.003 \({}^{\text{a}}\) & 0.029 \(\pm\) 0.008 \({}^{\text{c}}\) \\ \hline \hline \end{tabular}  
* LA-p: was fermented with _L. acidophilus_, LB-p: was fermented with _L. valesi_, LC-p: was fermented with _L. helicticus_, BB-p: was fermented with _B. bifidum_, and ST-p: was fermented with _S. thermophilus_. \({}^{\text{*}}\) Each parameter was evaluated separately, and there was a statistically significant difference between groups that did not have a common letter (a–e) (p \(<\) 0.05). \({}^{\text{c}}\) Confidence interval of the arithmetic mean with a probability of 95%.  
\end{table} 
Table 2: _Cont._flavors in fermented products [37]. However, here, the LC-p sample with low citric acid value, and therefore the _L. casei_ strain, stands out because the acetoin amount that increases with the use of citric acid during fermentation and its decrease (data are available in the volatile aroma components section) shows that the _L. casei_ strain produces acetoin by using the citrate present in normal milk (130-160 mg citrate per 100 mL). Thus, the determination of high amounts of acetoin in a sample with low citric acid also shows the supportive relationship between the analyses in this study. On the other hand, the acetoin amount is also second highest in the ST-p sample. Here, despite the high citric acid in the ST-p sample, this observation can be explained by the view that the _S. thermophilus_ strain also causes the conversion of citric acid to acetoin, but the speed and amount of this conversion are slightly lower than in the _L. casei_ strain. Similarly, in one study, it was stated that _L. paracasei_ and _S. thermophilus_ strains were involved in this conversion between citric acid and acetone [38]. As for formic acid, a minor organic acid in the overall profile, if it is present in excessive concentrations, an undesirable sharp taste may occur in the product. The LB-p and BB-p samples had the most high values of it (0.164 and 0.163, respectively), following the LA-p sample. This result corresponds to heterofermentative pathways where formic acid is generated as a byproduct [39]. In addition, these strains also have probiotic properties, which is the most negative aspect in terms of aroma. _B. bifidum_ strains demonstrate strong acidification capability, highlighting its contribution to gut health. Its acid profile supports its application in symbiotic formulations [39]. When the total content of organic acids detected in this study is examined, the observation that the BB-p sample has the highest content supports this situation.