## 3 Results and Discussions
### Color of Dough and Bread
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Leaves’ Share** & & & & \\ (_uv/v Flour Basis_) & **L*** & **a*** & **b*** & **\(\Delta\)E** \\
**[\%]** & & & & \\ \hline \hline
0.0 (control) & 80.4 \({}^{\mathrm{f}}\)\(\pm\) 0.5 & 1.71 \({}^{\mathrm{d}}\)\(\pm\) 0.04 & 15.4 \({}^{\mathrm{a}}\)\(\pm\) 0.2 & & \\
0.5 (A) & 74.9 \({}^{\mathrm{e}}\)\(\pm\) 0.7 & \(-\)1.83 \({}^{\mathrm{c}}\)\(\pm\) 0.23 & 23.2 \({}^{\mathrm{b}}\)\(\pm\) 1.0 & 10.1 \({}^{\mathrm{a}}\)\(\pm\) 1.2 \\
1.0 (B) & 68.6 \({}^{\mathrm{d}}\)\(\pm\) 0.6 & \(-\)1.74 \({}^{\mathrm{c}}\)\(\pm\) 0.08 & 25.6 \({}^{\mathrm{c}}\)\(\pm\) 2.0 & 16.0 \({}^{\mathrm{b}}\)\(\pm\) 1.3 \\
1.5 (C) & 66.0 \({}^{\mathrm{c}}\)\(\pm\) 0.1 & \(-\)3.09 \({}^{\mathrm{a}}\)\(\pm\) 0.01 & 28.6 \({}^{\mathrm{d}}\)\(\pm\) 0.1 & 20.1 \({}^{\mathrm{c}}\)\(\pm\) 0.2 \\
2.0 (D) & 62.9 \({}^{\mathrm{b}}\)\(\pm\) 0.1 & \(-\)3.08 \({}^{\mathrm{a}}\)\(\pm\) 0.03 & 28.3 \({}^{\mathrm{d}}\)\(\pm\) 0.1 & 22.3 \({}^{\mathrm{d}}\)\(\pm\) 0.2 \\
2.5 (E) & 59.2 \({}^{\mathrm{a}}\)\(\pm\) 0.1 & \(-\)3.65 \({}^{\mathrm{a}}\)\(\pm\) 0.01 & 27.1 \({}^{\mathrm{d}}\)\(\pm\) 0.1 & 24.8 \({}^{\mathrm{e}}\)\(\pm\) 0.2 \\ \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, 15, 2.0 and 2.5% levels, respectively. AE: total color difference.  
\end{table} 
Table 3: Color of wheat dough with _J. regia_ leaves. In relation to the analysis of bread color (crust and crumb), similarly to [PERSON] et al. [32] and [PERSON] et al. [30], a decrease in the value of the L* parameter was observed for both the crust and crumb. However, the a* parameter in the crumb color of all the breads had positive values, and, similarly to the b* parameter, its value increased as the WLs content increased (Table 4), and as a consequence, an increase in the total color difference (\(\Delta\)E) was noted. The average value of the L* parameter of the crust and crumb of the breads containing WLs was 56.27 and 46.10, respectively, and was lower compared to the values recorded in the control tests by approximately 10% and 37%, respectively, for the crust and crumb. The parameter a* and the parameter b* took positive values, which indicates a dominant share of red and blue colors, respectively. In both the crust and crumb, a clear increase in the value of the \(\Delta\)E parameter was observed with the increasing share of WLs in the recipe of the tested bread. This is confirmed by the noticeable darkening of the color under the influence of the discussed plant additive (Figure 1). A similar pattern of changes in the color of the crust and crumb of the wheat bread containing dried walnut flower powder was recorded in a study by [PERSON] et al. [16]. [PERSON] et al. [33] examined the color of wheat bread enriched with extracts from plant byproducts (extracts from chicory, cabbage, celery, fennel, olive leaf and grape marc wastes) and found that replacing water with extracts resulted in a significant reduction in the brightness of the crumb and a shift in color towards a red color. In the case of the b* parameter, it was found that the color of the enriched bread had yellowish shades, while the color of the bread with celery extract was similar to the control sample. The darkening of the crust and crumb color of gluten-free bread enriched with _Moringa oleifera_ leaf powder was also confirmed by [PERSON] et al. [23]. As the cited authors explain, the color change results from the high chlorophyll content in the tested plant additive. In the analyzed case, the colors of both the dough and bread (crust and crumb) are determined by the chemical composition of the walnut leaves. According to [PERSON] [36] and [PERSON] et al.