# Volatile Organic Compounds in Breads Prepared with Different Sourdoughs
## 3 Results  
### Microbiological and Physicochemical Analysis  
In Table 2, the microbiological composition and physicochemical results of sourdoughs after 8 months of stabilization are shown. The yeasts and bacteria were present in the highest amounts in S4 sourdough, with bacteria at a concentration of 6.55 \(\times\) 10\({}^{8}\) CFU/g and yeasts at a concentration of 5.65 \(\times\) 10\({}^{7}\) CFU/g. Although S4 was prepared with only yeast beer, after 8 months of stabilization, bacteria were also found, indicating the growth of natural bacteria (Table 2). S3 and S2 prepared with the same bacteria/yeast ratio showed a different ratio after 8 months: S3 had a higher ratio than S2 (159.15 vs. 47.05). S3 sourdough was prepared with wheat flour type 0 and wheat flour type 00 at a ratio of 3:1, while S2 sourdough was prepared with wheat flour type 00 and Manitoba flour at a ratio of 80:20. The type of flour used could influence the sourdough composition [21]. The species of bacteria found was _Lactobacillus surfancisensis_, while for yeast, _Saccharomyces cerevisiae_ was found. Furthermore, in sourdough S1, the yeast _Kazachstania unispora_ was also found. The pH value ranged between 3.87 in S4 and 4.22 in S3. The pH of a stabilized sourdough is influenced by the nature of the process and starter culture used, and generally, it ranges from 3.5 to 4.3 in wheat sourdoughs [2]. The TA ranged between 6.32 mL of NaOH/10 g of sample in S3 to 7.32 mL of NaOH/10 g of sample in S4. The values were in accordance with [PERSON] et al. [18], who showed a value that ranged between 3.5 and 9.7 mL of NaOH/10 g of the sample depending on the cultures used to prepare sourdoughs. The trend of the pH value of dough bread during fermentation is shown in Figure 1. At the beginning of fermentation, the pH was in the range of 5.56-5.63, while at the end of fermentation, it ranged between 4.22 in S1 and 4.30 in S4. The pH value at the end of fermentation was over 4.1, according to [PERSON] et al. [22], who showed a pH value that ranged between 4.73 and 5.03 depending on the concentration of sourdough used for the preparation of bread. \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**Samples** & **Bacteria/Vessels Ratio** & **Bacteria (CFUg)** & **Yessels (CFUg)** & **Predominant Yeast Species** & **Predominant Bacteria Species** & pH & **Timetable Assembly test** \\ \hline S1 sourdoughs & 12.75 & 3.25 \(\times\) 10\({}^{8}\) \(\pm\) 0.27 & 2.55 \(\times\) 10\({}^{8}\) \(\pm\) 1.1 & S. cerevisiae & \(L\) surfancispora & 4.02\({}^{\circ}\) \(\pm\) 0.01 & 6.33\({}^{\circ}\) \(\pm\) 0.01 \\ S2 sourdoughs & 4\(\aas@@fstack{\prime}\)0.65 & 4.00 \(\times\) 10\({}^{8}\) \(\pm\) 1.27 & 8.50 \(\times\) 10\({}^{6}\) \(\pm\) 1.27 & S. cerevisiae & \(L\) surfancispora & 4.09\({}^{\circ}\) \(\pm\) 0.01 & 6.50\({}^{\circ}\) \(\pm\) 0.01 \\ S3 sourdoughs & 159.15 & 5.65 \(\times\) 10\({}^{8}\) \(\pm\) 0.35 & 3.85 \(\times\) 10\({}^{6}\) \(\pm\) 0.07 & S. cerevisiae & \(L\) surfancispora & 4.22\({}^{\circ}\) \(\pm\) 0.01 & 6.32\({}^{\circ}\) \(\pm\) 0.03 \\ S4 sourdoughs & 11.59 & 6.55 \(\times\) 10\({}^{8}\) \(\pm\) 0.21 & 5.65 \(\times\) 10\({}^{8}\) \(\pm\) 0.35 & S. cerevisiae & \(L\) surfancispora & 3.87\({}^{\circ}\) \(\pm\) 0.01 & 7.32\({}^{\circ}\) \(\pm\) 0.03 \\ \hline \hline \end{tabular}  
* a-d: different letters in the same column indicate statistically significant difference (\(p\) < 0.05).  
\end{table} 
Table 2: Microbiological characterization, pH value, tittatable acidity of 8 months refreshed sourdoughs used to produce bread. The moisture and a\({}_{w}\) values of bread in Table 3 are shown, and a positive correlation between them was found. S1 and S4 showed the highest values of both moisture and a\({}_{w}\), while S3 showed the lowest value. The moisture content ranged between 22.99 g/100 g in bread S3 and 28.20 g/100 g in S1. According to G.U. 189/1967 [17], the moisture content does not exceed 34% in any bread samples. The moisture content was lower than the value reported by [PERSON] et al.