## 3 Results and Discussions
### Parameters of the Laboratory Baking Process
The conducted research (Table 2) showed that the share of WLs in the bread recipe resulted in a significant reduction in the value of this parameter (\(p\leq 0.05\)) in the tested bread. Similar observations were reported by [PERSON] et al. [30] and [PERSON] et al. [16] in their studies on the effect of supplementing wheat flour with appropriately dried parsley leaves and walnut flowers. Similarly, [PERSON] et al. [33] found a decrease in the specific volume of wheat bread enriched with plant extracts (celery, chicory, cabbage, fennel, olive leaves, grape pomace). The specific volume decreased in the order control \(>\) fennel \(>\) grape pomace \(>\) chicory and celery \(>\) cabbage and olive leaves. According to [PERSON] et al. [33], the reduction in bread volume may result from the action of the acidic plant extract components denaturing the gluten network. Moreover, the bioactive substances present in the extract modified the physical properties of the bread dough. This was due to the possibility of forming complexes between antioxidants and proteins and polysaccharides, stabilized by hydrogen and covalent bonds. The hydrophobic bonds in the polyphenol-protein system are also responsible for the stability of the complexes [34]. Moreover, the participation of WLs in the dough recipe could have an adverse effect on the \begin{table}
\begin{tabular}{c c c c c} \hline
**Leaves’ Share** & **Dough** & **Oven** & **Total** & **Bread** \\ (_w/tv_ **Four Basis)** & **Yield** & **Loss** & **Baking Loss** & **Yield** \\
**[\%]** & **[\%]** & **[\%]** & **[\%]** & **[\%]** \\ \hline
0.0 (control) & 160 \({}^{\text{a}}\)\(\pm\) 1 & 7.0 \({}^{\text{ab}}\)\(\pm\) 0.1 & 12.6 \({}^{\text{ab}}\)\(\pm\) 0.0 & 140 \({}^{\text{a}}\)\(\pm\) 0 \\
0.5 (A) & 161 \({}^{\text{a}}\)\(\pm\) 1 & 6.6 \({}^{\text{a}}\)\(\pm\) 0.6 & 11.4 \({}^{\text{a}}\)\(\pm\) 0.3 & 142 \({}^{\text{b}}\)\(\pm\) 1 \\
1.0 (B) & 163 \({}^{\text{a}}\)\(\pm\) 0 & 7.9 \({}^{\text{bc}}\)\(\pm\) 0.7 & 12.1 \({}^{\text{ab}}\)\(\pm\) 0.6 & 143 \({}^{\text{b}}\)\(\pm\) 1 \\
1.5 (C) & 159 \({}^{\text{a}}\)\(\pm\) 2 & 7.0 \({}^{\text{ab}}\)\(\pm\) 0.0 & 11.7 \({}^{\text{ab}}\)\(\pm\) 0.2 & 140 \({}^{\text{a}}\)\(\pm\) 0 \\
2.0 (D) & 163 \({}^{\text{a}}\)\(\pm\) 1 & 6.8 \({}^{\text{ab}}\)\(\pm\) 0.7 & 11.5 \({}^{\text{ab}}\)\(\pm\) 0.8 & 144 \({}^{\text{b}}\)\(\pm\) 1 \\
2.5 (E) & 164 \({}^{\text{a}}\)\(\pm\) 2 & 8.3 \({}^{\text{c}}\)\(\pm\) 0.4 & 12.7 \({}^{\text{b}}\)\(\pm\) 0.5 & 143 \({}^{\text{b}}\)\(\pm\) 1 \\ \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 1: Laboratory baking parameters of wheat dough with _J. regia_ leaves. activity of yeast, the product of which is, among others, carbon dioxide. This may be due to the antibacterial properties of the leaves of _Iuglans regia_ L., as confirmed by the research of [PERSON] et al. [20]. WLs selectively inhibited the growth of Gram-positive bacteria. _Bacillus cereus_ was the most susceptible one (MIC 0.1 mg/mL). However, Gram-negative bacteria and fungi were resistant to the extracts at 100 mg/mL. Moreover, the tests used wheat flour, which is the only flour that contains gliadin and glutenin in appropriate proportions. The gluten that forms is responsible for the volume of the loaves and the hardness of the crumb. The use of a plant additive instead of flour results in a dilution of the gluten in the dough and thus reduces the volume of the resulting bread [30]. However, [PERSON] et al. [32] observed an increase in the specific volume of gluten-free bread enriched with dried broccoli leaves. According to the cited authors, prior heat treatment of the leaves by blanching resulted in the inactivation of enzymes and thus did not show any inhibitory effect on the activity of yeasts responsible for the fermentation process.