## 3 Results and Discussions
### Color of Dough and Bread  
Tables 3 and 4 present the average values of the parameters for the instrumental color analysis of the dough and bread, respectively, according to the developed recipe. It was shown that the use of WLs had a statistically significant effect (\(p\leq 0.05\)) on all the analyzed parameters. In the case of dough (Table 3), it was found that the highest value of the L* parameter, informing about the brightness of the sample, was characteristic for the control sample, and the addition of WLs resulted in a statistically significant reduction in the value of this parameter (\(p\leq 0.05\)) (from 80.43 (control) to 59.17 (E)). In turn, the a* parameter in the dough samples containing WLs took on negative values, which indicates a greater share of green color, increasing with the increase in the WLs content in the bread recipe. An \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Leaves’ Share** & **Bread Volume** & **Specific Volume [cm\({}^{3}\)/g]** & **Crump Porosity Index** \\
**[**Va**]** & **[cm\({}^{3}\)]** & & \\ \hline
0.0 (control) & 533 \({}^{\circ}\)\(\pm\) 18 & 2.44 \({}^{\circ}\)\(\pm\) 0.08 & 80 \({}^{\circ}\)\(\pm\) 0 \\
0.5 (A) & 465 \({}^{\circ}\)\(\pm\) 21 & 2.09 \({}^{\circ}\)\(\pm\) 0.10 & 80 \({}^{\circ}\)\(\pm\) 0 \\
1.0 (B) & 450 \({}^{\circ}\)\(\pm\) 0 & 2.04 \({}^{\circ}\)\(\pm\) 0.01 & 80 \({}^{\circ}\)\(\pm\) 0 \\
1.5 (C) & 435 \({}^{\circ}\)\(\pm\) 14 & 1.97 \({}^{\circ}\)\(\pm\) 0.07 & 80 \({}^{\circ}\)\(\pm\) 0 \\
2.0 (D) & 423 \({}^{\circ}\)\(\pm\) 11 & 1.91 \({}^{\circ}\)\(\pm\) 0.07 & 80 \({}^{\circ}\)\(\pm\) 0 \\
2.5 (E) & 420 \({}^{\circ}\)\(\pm\) 14 & 1.92 \({}^{\circ}\)\(\pm\) 0.06 & 70 \({}^{\circ}\)\(\pm\) 0 \\ \hline \hline \end{tabular} The means marked in the columns with the same letters do not differ at the significance level \(p\leq 0.05\). A–E: the systems in which the flour was replaced with walnut leaf powder at 0.5, 1.0, 1.5, 2.0 and 2.5% levels, respectively.  
\end{table} 
Table 2: Bread volume of wheat dough with _J. regia_ leaves. Figure 1: External appearance of the loaf and crumb of the control and test breads. (**A–E**): the systems in which the flour was replaced with walnut leaf powder at 0.5, 1.0, 1.5, 2.0 and 2.5% levels, respectively. increase in the value of the b* parameter, which is a measure of the share of yellow/blue color, was also found. The value of the total color difference (\(\Delta\)E) of the samples with WLs increased statistically significantly compared to the control sample because the higher the value of this parameter, the easier it is to notice color differences with the naked eye. To classify differences in the perceived color of the wheat bread control sample and the wheat bread with WLs addition, the criterion given by [PERSON] et al. (2018), very distinct (\(\Delta\)E \(>\) 3), distinct (1.5 \(<\)\(\Delta\)E \(<\) 3) and small difference (\(\Delta\)E \(<\) 1.5), was applied. Differences in the color of the dough are the result of the substitution of wheat flour with WLs. WLs contain chlorophyll, which determines the green shade of the color of both the dough and bread, and the greater the proportion of WLs, the greater this green shade. A similar tendency was noticed by [PERSON] et al. (2018) when analyzing the color of gluten-free bread enriched with dried broccoli leaf powder (BLP). The cited authors also confirmed a decrease in the value of the L* parameter; the a* parameter had negative values, and the b* parameter had higher values with the increasing share of BLP. The cited authors explained this color change by the well-preserved ingredients of the raw material in the freeze-drying process. A similar pattern of changes in the color of the crumb of wheat bread enriched with powdered parsley leaves was observed by [PERSON] et al. (2018). In the described studies, walnut leaves (Table 3) were also dried using the freeze-drying method. The dough took on a greenish color, and the bread, as a result of the braking process and the thermal degradation of dyes, turned brown.