## 3 Results and Discussion
### Composition and Physical Properties of Bread
These results indicate that the crumb of bread enriched in this way is characterized by a greater number of fine pores, which may favorably influence the acceptance of its structure. The determined color parameters (Figure 4a) also indicate significant changes in the appearance of the crumb. The highest value of the crumb L* parameter had the control bread indicating the brightness of the sample, and the presence of kale significantly (_p_ < 0.05) reduced it. The a* parameter of the control sample showed positive values indicating the contribution of the red color. In contrast, the presence of lyophilized kale caused a shift in the value of this parameter toward negative values, indicating an increasing proportion of green color. Similarly, in the case of the parameter b* indicating the contribution of yellow color, bread with kale powder had significantly (_p_ < 0.05) higher values for this parameter than the control sample, but without a clear effect of the enrichment level itself (Figure 4a). The changes in crumb color characteristics are due to the introduction of kale powder, the natural plant tissue pigments. The contents of chlorophylls a, b, their sum, and carotenoids in the control bread and samples with lyophilized kale are shown in Figure 4b. As the amount of kale lyophilize increased, the content of individual pigments increased significantly (_p_ < 0.05). The obtained results on color change reflect the literature data, which indicate that the use of vegetable or vegetable industry waste as ingredients in bakery products significantly affects their color [43]. [PERSON] et al. [44] observed a significantly darker color of the crumb and crust of gluten-free bread enriched with a broccoli-based preparation. In addition, such bread showed significantly lower negative values of the a* parameter and significantly higher values of the b* parameter than control bread, indicating an increase in the proportion of green and yellow color. Also, according to \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Parameter** & **Control** & **5\% KP** & **10\% KP** & **Anova-_p_ \\ \hline Volume (cm\({}^{3}\)) & 120 \(\pm\) 7 a & 114 \(\pm\) 5 a & 108 \(\pm\) 8 a & 0.060 \\ Specific volume (cm\({}^{3}\cdot\)g\({}^{-1}\)) & 2.86 \(\pm\) 0.18 a & 2.70 \(\pm\) 0.11 a & 2.55 \(\pm\) 0.23 a & 0.054 \\ Average pore size (mm\({}^{2}\)) & 0.973 \(\pm\) 0.055 b & 0.890 \(\pm\) 0.026 a & 0.810 \(\pm\) 0.036 a & 0.008 \\ Porosity & 0.443 \(\pm\) 0.006 & 0.420 \(\pm\) 0.010 & 0.407 \(\pm\) 0.029 & 0.113 \\ Cell density (cm\({}^{-2}\)) & 44.9 \(\pm\) 3.1 a & 49.9 \(\pm\) 0.9 ab & 53.6 \(\pm\) 3.4 b & 0.021 \\ Percentage of pores \textgreater{} 5 mm\({}^{2}\) & 3.68 \(\pm\) 0.73 b & 2.75 \(\pm\) 0.20 b & 1.48 \(\pm\) 0.29 a & 0.004 \\ \hline \hline \end{tabular} Mean value of four replications \(\pm\) standard deviation. Means in rows marked with the same letters do not differ statistically at a 0.05 level of confidence.  
\end{table} 
Table 2: Physical characteristics of the investigated wheat and wheat-kale (KP) composite bread. [PERSON] et al. [38], bread enriched with a broccoli-based preparation has a higher intensity of green color, both in the crust and crumb. However, according to [PERSON] et al. [45], this can adversely affect the acceptability of such products.