## 3 Results and Discussion  
Table 1 presents selected color coordinates measured colorimetrically in the CIELab system in the products made based on maize semolina with different contents of pomace from two varieties of flax: golden flax and common flax, with and without added cocoa. The color coordinates depended to a statistically significantly extent on all statistical factors analyzed (type of flax pomace, its content in the product, and cocoa addition). The highest brightness value (L) was measured in the corn snacks produced without the addition of cocoa and without the addition of flaxseed pomace (77.26). The addition of each type of flaxseed pomace led to a decrease in the brightness value, whereas the snacks produced with the addition of golden flasseed pomace had a statistically higher L value (69.88) compared to those with common flaxseed pomace (68.11). Similar results were obtained in the analysis of the chroma value, which was 22.20 in the snacks with the addition of golden flasseed pomace and 20.72 in those with common flaxseed pomace. In turn, when analyzing the color hue angle, there were no statistically significant differences in its values as affected by the type of pomace used (Table 1). Analyzing the effect of only the content of pomace on snack brightness, it was found that the highest brightness value was recorded in the case of the products without the pomace (72.16), and the lowest in those with 15% content of the pomace (66.10). However, each of the analyzed pomace addition levels caused a statistically significant decrease in the value of this color coordinate (Table 1). The same correlations were noted in the case of chroma and hue angle values. Other authors also achieved similar values in their works with snacks [6; 23; 24; 25], pasta [8], cookies [26], muffins [27], bread or breadcrumbs. The decrease in the color coordinates recorded in the products with flaxseed pomace is mainly due to the dark color of flaxseeditself [9]. [PERSON] et al. in their work with extruded products based on maize semolina also obtained products with a darker color after adding flaxseed pomace compared to the snacks produced without pomace [23]. However, the reduction in color parameters of products reported by these authors was much lower than in the products manufactured by other authors, despite similar proportions of flaxseed pomace in the snack formulas. These differences were due to the fact that [PERSON] et al. [23] used only golden flaxseed pomace, whose color is much lighter (yellow) than that of pomace obtained from common flax pressing (dark brown). The darker color of common flaxseed pomace is due to its chemical composition as the common flax variety was found to contain significantly more fiber, lignans, phytosterols and associated pigments than the golden flax variety [6]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
When comparing the values describing the color of products produced without and with cocoa, it was found that cocoa addition caused a statistically significant decrease in their brightness (65.00) and shifted the hue angle value toward red colors (79.05) compared to the snacks produced without cocoa addition in which these values were 72.99 and 85.31, respectively. These results are due to the dark color of cocoa used in the study (L = 63.14 \(\pm\) 0.03; a = 1.95 \(\pm\) 0.02; b = 25.33 \(\pm\) 0.02), which is ascribed to its phenolic and flavonoid pigments. Other authors also achieved similar or even greater reductions in color brightness of products extruded with cocoa addition [28,29]. In their work, [PERSON] and others obtained up to 50% reduction in brightness of the products with a 5% cocoa addition (2013). This was, undoubtedly, due to the use of a larger cocoa addition, but also a lower extrusion temperature (130 \({}^{\circ}\)C), which caused lesser degradation of the cocoa pigments [28], and higher moisture content of the extruded mixture [12].