## 3 Results and Discussion
### Characteristics of Extruded Corn Snacks
#### 3.2.2 Quality of Extruded Corn Snacks with Fruit Pomace  
Some of the most important parameters for the qualitative evaluation of extruded snack products are density and expansion, especially in terms of assessing their textural properties [63]. Expansion and density of extrudates are quantities that are most often inversely proportional; that is, as the expansion factor increases, the density decreases [47; 62]. Both quantities are largely dependent on the dietary fiber (DF) content, especially its soluble and insoluble fractions (SDF and IDF). It was observed that adding chokeberry, cherry, and blackcurrant pomace increased the extrudates' density, with the higher the level of additive used, the higher the density relative to the control. With a 20% level of the various additives, the density of the extruded snacks was almost 1.5 to 2 times higher as compared to the control. In contrast to the 5% additive, which did not affect this parameter regardless of the type of additive used (pomace-cherry, chokeberry, or blackcurrant) (Table 5). It was found that the expansion of extruded snacks with fruit pomace did not change in relation to the control, regardless of the proportion of such an additive (Table 5). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Density [g/cm\({}^{3}\)]** & **Expansion Ratio [\%]** & **WBC \({}^{1}\) [\%]** \\ \hline Control & 0.064 \(\pm\) 0.01 \({}^{\text{a}}\) & 4.24 \(\pm\) 0.76 \({}^{\text{a}}\) & 4.38 \(\pm\) 0.12 \({}^{\text{e}}\) \\ ECHB-05 & 0.072 \(\pm\) 0.01 \({}^{\text{a}}\) & 4.58 \(\pm\) 0.25 \({}^{\text{a}}\) & 3.21 \(\pm\) 0.09 \({}^{\text{c}}\) \\ ECHB-10 & 0.118 \(\pm\) 0.01 \({}^{\text{c}}\) & 4.23 \(\pm\) 0.13 \({}^{\text{a}}\) & 2.84 \(\pm\) 0.00 \({}^{\text{b}}\) \\ ECHB-20 & 0.138 \(\pm\) 0.00 \({}^{\text{d}}\) & 4.18 \(\pm\) 0.15 \({}^{\text{a}}\) & 2.34 \(\pm\) 0.07 \({}^{\text{a}}\) \\ ECH-05 & 0.059 \(\pm\) 0.02 \({}^{\text{a}}\) & 4.11 \(\pm\) 0.18 \({}^{\text{a}}\) & 3.58 \(\pm\) 0.00 \({}^{\text{d}}\) \\ ECH-10 & 0.084 \(\pm\) 0.00 \({}^{\text{ab}}\) & 4.29 \(\pm\) 0.30 \({}^{\text{a}}\) & 2.99 \(\pm\) 0.17 \({}^{\text{b}}\) \\ ECH-20 & 0.110 \(\pm\) 0.02 \({}^{\text{c}}\) & 4.12 \(\pm\) 0.09 \({}^{\text{a}}\) & 2.57 \(\pm\) 0.21 \({}^{\text{a}}\) \\ EBC-05 & 0.073 \(\pm\) 0.02 \({}^{\text{a}}\) & 3.89 \(\pm\) 0.11 \({}^{\text{a}}\) & 3.37 \(\pm\) 0.00 \({}^{\text{c}}\) \\ EBC-10 & 0.087 \(\pm\) 0.02 \({}^{\text{ab}}\) & 4.05 \(\pm\) 0.25 \({}^{\text{a}}\) & 2.87 \(\pm\) 0.03 \({}^{\text{b}}\) \\ EBC-20 & 0.127 \(\pm\) 0.02 \({}^{\text{d}}\) & 4.03 \(\pm\) 0.23 \({}^{\text{a}}\) & 2.42 \(\pm\) 0.05 \({}^{\text{a}}\) \\ \hline \hline \end{tabular} The values in the column marked with the same letter are not significantly different at \(p=0.05\). \({}^{\text{i}}\) WBC—water binding capacity.  
\end{table} 
Table 5: Physical properties of extrudates of corn extrudates with addition of fruit pomace. The expansion of the extruded snacks is mainly ensured by the starch present in the mixture, which is characterized by viscoelastic properties. Bubbles formed by the evaporation of the water present in the extruded material penetrate into the swelling starch granules and cause them to expand [24]. As a result of replacing cornmeal, which is a source of starch, with fruit pomace, which in turn is a source of dietary fiber, there is, among other things, a reduction in the extensibility of the bubbles formed, which has the effect of reducing the expansion ratio and increasing the density of the obtained extruded products [64]. In addition to the above-described reduction in gas bubbles, the IDF fraction also causes their damage, acting as a disintegrating agent [25]. In addition, the SDF fraction (mainly pectin) present in the pomace, which is characterized by a high water-absorbing capacity, contributes to starch water-absorption reduction, thus inhibiting the expansion process of the product [25].