# The Influence of Chestnut Flour on the Quality of Gluten-Free Bread
## 3 Results and Discussion  
### Physical Properties  
The breads with the chestnut flour in the amounts of 5, 10, 15 and 20% were analyzed, as well as the control sample, which was bread without the addition of chestnut flour. By analyzing the obtained results of the average weight value after baking (Table 2), it was found that the lowest weight characterized bread with a 10% addition of chestnut flour (153.88 g) followed by the control sample (160.97 g). No statistically significant differences were noticed in the case of the control sample and the bread with the 5% addition of chestnut flour. Moreover, no statistically significant differences were found for the weight of the bread with the 15% addition of chestnut flour and the weight of bread with the 20% addition of chestnut flour (166.69 g), which was characterized by the highest weight among all variants. The highest volume (310.4 cm\({}^{3}\)/100 g) among the gluten-free breads was characteristic for the bread with the 10% addition of chestnut flour (Table 2). No statistically significant differences were found between the bread with the 10% addition of chestnut flour and the bread with the 5% addition of chestnut flour (283.8 cm\({}^{3}\)/100 g). Comparing the variant without the addition of chestnut flour, with the breads with the 15% and 20% flour additions, no statistically significant differences were found in the values of this parameter. The value of this characteristic for breads with a variable addition of chestnut flour ranged from 207 cm\({}^{3}\)/100 g to 310.4 cm\({}^{3}\)/100 g. According to the standard for gluten-free bread [38], the volume of 100 g of bread should be no less than 190 cc. All the values obtained in the experiment are within the optimum range. Taking into account the obtained results, it was found that the addition of 5 and 10% chestnut flour to the recipe causes an increase in the \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample** & **Finished Product** & **Volume** & **Specific Mass** & **Porosity** \\  & **Weight [g]** & **[cm\({}^{3}\)/100 g]** & **[g/cm\({}^{3}\)]** & **[\%]** \\ \hline Control & 160.97 \(\pm\) 1.64 b & 207.00 \(\pm\) 7.35 a & 0.27 \(\pm\) 0.02 c & 73.46 \(\pm\) 1.02 c \\
5\% & 162.11 \(\pm\) 2.13 b & 283.8 \(\pm\) 8.47 b & 0.20 \(\pm\) 0.03 b & 69.75 \(\pm\) 1.07 b \\
10\% & 153.88 \(\pm\) 1.63 a & 310.4 \(\pm\) 6.69 b & 0.17 \(\pm\) 0.03 a & 74.07 \(\pm\) 1.00 c \\
15\% & 165.73 \(\pm\) 1.78 c & 215.22 \(\pm\) 7.41 a & 0.20 \(\pm\) 0.02 b & 72.22 \(\pm\) 1.65 c \\
20\% & 166.69 \(\pm\) 1.65 c & 224.00 \(\pm\) 5.65 a & 0.25 \(\pm\) 0.03 c & 64.81 \(\pm\) 1.83 a \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Weight, volume, specific weight and porosity of gluten-free bread with the addition of chestnut flour in the amount of 0, 5, 10, 15 and 20%. volume of the tested breads. Increasing the percentage of the addition of this flour causes a decrease in the baking volume. Similar relationships were obtained by [PERSON] [39] in a study of the effect of chestnut flour leaven on the properties of gluten-free bread. The breads contained 15, 20 and 25% chestnut flour, and the basic raw material was corn starch. The increase in the concentration of chestnut flour caused a decrease in the volume of the bread. The research conducted by [PERSON] [40] on an attempt to replace rice flour with chestnut flour in bread showed that the volume of the bread increases with increasing the ratio of chestnut flour to rice flour. These differences may be due to the use of flour with different dietary fiber content. In this study, flour with the amount of fiber of 16% was used, whereas the amount of fiber in the flour used by [PERSON] [39] was 15%, but [PERSON] [40] used chestnut flour with a fiber content of 9.5%. Due to its gas retention and viscoelastic properties, fiber can increase the volume of gluten-free bread. Too much fiber reduces the volume of the bread. These differences may also be caused by the use of various types of technological additives, e.g., emulsifiers [39].