# Gluten-Free Sourdough Based on Quinoa and Sorghum: Characterization and Applications in Breadmaking
## 3 Results
### 3.4. Bread Properties
No significant differences in terms of specific volume were noted among the three different Q50-based bread samples. Except for the Q50 SC2 which presented the highest firmness of 32.79 N (_p_ < 0.05), the texture of the GF sourdough bread samples was not significantly influenced by the amount of sorghum flour in the blend, or the type of starter culture used for initiating the fermentation (Table 10). The increase in the sorghum level of the GF flour blends caused a significant increase in the L* values of the bread samples (_p_ < 0.05). The positive values of the a* and b* parameters indicated the presence of red and yellow color in all investigated GF sourdough bread samples. The type of starter culture used for sourdough fermentation influenced in different manners the color properties of the GF bread. Except for the Q75-based bread, the intensity of the yellow shades of the bread increased (_p_ < 0.05) with the use of starter culture for sourdough fermentation (Table 10). The presence of the red color in the sorghum-containing bread was not influenced by the starter culture used for sourdough fermentation. The results of the sensory analysis of the GF sourdough bread are presented in Figure 5. Quinoa flour substitution with sorghum flour resulted in sourdough bread with signifi \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Sample** & **Specific Volume, cm\({}^{3}\)/g** & **L*** & **a*** & **b*** & **Firmness, N** \\ \hline Q100 C & 133.9 \(\pm\) 6.3 \({}^{\text{a,A}}\) & 43.93 \(\pm\) 0.30 \({}^{\text{c,B}}\) & 3.41 \(\pm\) 0.02 \({}^{\text{a,B}}\) & 16.63 \(\pm\) 0.10 \({}^{\text{a,B}}\) & 26.14 \(\pm\) 1.40 \({}^{\text{a,A}}\) \\ Q75 C & 109.2 \(\pm\) 6.4 \({}^{\text{a,A}}\) & 47.18 \(\pm\) 0.26 \({}^{\text{b,A}}\) & 3.25 \(\pm\) 0.01 \({}^{\text{b,A}}\) & 16.48 \(\pm\) 0.11 \({}^{\text{a,A}}\) & 27.09 \(\pm\) 0.93 \({}^{\text{a,A}}\) \\ Q50 C & 110.8 \(\pm\) 6.5 \({}^{\text{a,A}}\) & 50.05 \(\pm\) 0.37 \({}^{\text{a,A}}\) & 2.79 \(\pm\) 0.02 \({}^{\text{c,A}}\) & 15.76 \(\pm\) 0.08 \({}^{\text{b,B}}\) & 29.11 \(\pm\) 5.12 \({}^{\text{a,A}}\) \\ \hline Q100 SC1 & 124.4 \(\pm\) 6.3 \({}^{\text{a,A}}\) & 45.14 \(\pm\) 0.20 \({}^{\text{c,A}}\) & 3.31 \(\pm\) 0.00 \({}^{\text{a,C}}\) & 17.15 \(\pm\) 0.09 \({}^{\text{a,A}}\) & 27.20 \(\pm\) 1.53 \({}^{\text{a,A}}\) \\ Q75 SC1 & 131.6 \(\pm\) 6.6 \({}^{\text{a,A}}\) & 45.96 \(\pm\) 0.09 \({}^{\text{b,B}}\) & 3.19 \(\pm\) 0.01 \({}^{\text{a,A}}\) & 16.29 \(\pm\) 0.39 \({}^{\text{a,A}}\) & 25.37 \(\pm\) 2.38 \({}^{\text{a,A}}\) \\ Q50 SC1 & 110.3 \(\pm\) 6.5 \({}^{\text{a,A}}\) & 47.42 \(\pm\) 0.21 \({}^{\text{a,B}}\) & 2.94 \(\pm\) 0.10 \({}^{\text{b,A}}\) & 16.50 \(\pm\) 0.01 \({}^{\text{a,A}}\) & 29.14 \(\pm\) 7.17 \({}^{\text{a,A}}\) \\ \hline Q100 SC2 & 97.1 \(\pm\) 6.9 \({}^{\text{a,B}}\) & 43.07 \(\pm\) 0.07 \({}^{\text{c,B}}\) & 3.96 \(\pm\) 0.01 \({}^{\text{a,A}}\) & 17.31 \(\pm\) 0.16 \({}^{\text{a,A}}\) & 23.19 \(\pm\) 2.65 \({}^{\text{b,A}}\) \\ Q75 SC2 & 100.0 \(\pm\) 6.4 \({}^{\text{a,B}}\) & 46.61 \(\pm\) 0.14 \({}^{\text{b,A}}\) & 3.32 \(\pm\) 0.30 \({}^{\text{a,A}}\) & 16.45 \(\pm\) 0.19 \({}^{\text{b,A}}\) & 25.20 \(\pm\) 0.51 \({}^{\text{b,A}}\) \\ Q50 SC2 & 117.0 \(\pm\) 6.4 \({}^{\text{a,A}}\) & 49.36 \(\pm\) 0.13 \({}^{\text{a,A}}\) & 2.92 \(\pm\) 0.01 \({}^{\text{b,A}}\) & 16.42 \(\pm\) 0.07 \({}^{\text{b,A}}\) & 32.79 \(\pm\) 3.34 \({}^{\text{a,A}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 10: The influence of quinoa flour substitution by sorghum flour and of starter culture used for sourdough fermentation on the specific volume, color values (L*, a* and b*) and firmness of the gluten-free bread samples. icantly better odor and appearance of the crumb and crust. On the other hand, the GF sourdough bread with high levels of sorghum flour presented significantly lower scores for taste and texture (\(p<0.05\)). The most pleasant taste was noticed in the case of the Q100 SC1 bread followed by Q75 SC1, which was characterized by a well-balanced combination of sweet and sour flavors.