## 3 Results and Discussion  
### Experimental Results  
The mean values and the corresponding standard deviations of the studied characteristics are presented in Table 3. The experimental data showed that the _ER_ changed from 1.51 to 2.74, the _BD_--from 0.111 to 0.186 g/cm\({}^{3}\), the feed moisture content--from 5.84% to 9.32%, the _PDI_--from 66.11% to 97.36%, and the _HD_--from 18.99 N to 30.68 N. The color characteristics varied as follows: between 55.07 and 66.36 for lightness \(L\), between 10.92 and 15.73 for redness \(a\), between 9.75 and 16.67 for yellowness \(b\). The _WSI_ changed from 22.76% to 43.19%, and the _WAI_ from 4.28 g/g to 6.53 g/g (Table 4).  
The influence of each independent variable on the physical and functional characteristics is presented in the standardized Pareto charts (Figure 1). Feed moisture content had a primary effect on _ER_, _BD_, _PDI_, and _HD_. This is in agreement with the results in [20; 21; 22]. The amount of chokeberry pomace had a primary effect on _MC_ and _WSI_. The working screw speed had the biggest effect on _WAI_, \(L\), \(a\) and \(b\). Insignificant was the effect of the amount of chokeberry pomace on _ER_, _PDI_, \(L\) and \(a\); the feed moisture content on _WSI_, _WAI_, \(a\) and \(b\); and the working screw speed on _BD_.  
\begin{table}
\begin{tabular}{c c c} \hline
**No.** & _WSI_, \%** & _WAI_, \(\mathbf{g/g}\) \\ \hline
1 & \(31.88\pm 2.51\) & \(4.49\pm 0.27\) \\
2 & \(31.21\pm 1.05\) & \(6.19\pm 0.18\) \\
3 & \(31.21\pm 1.05\) & \(5.81\pm 0.24\) \\
4 & \(28.61\pm 1.04\) & \(6.56\pm 0.05\) \\
5 & \(22.76\pm 1.04\) & \(5.50\pm 0.06\) \\
6 & \(41.61\pm 1.15\) & \(5.19\pm 0.78\) \\
7 & \(31.35\pm 0.80\) & \(4.56\pm 0.45\) \\
8 & \(43.19\pm 2.52\) & \(4.28\pm 0.21\) \\ \hline \end{tabular}
\end{table}
Table 4: Experimental results for functional characteristics of extrudates.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline
**No.** & _ER_ & \
\begin{tabular}{c} _BD_, \\ **g/cm\({}^{3}\)** \\ \end{tabular} & **MC, \%** &
\begin{tabular}{c} _PDI_, \\ **\%** \\ \end{tabular} & **HD, N** & **L** & \(a\) & \(b\) \\ \hline
1 & \(2.74\pm 0.06\) & \(0.111\pm 0.013\) & \(8.37\pm 0.80\) & \(66.11\pm 1.15\) & \(18.99\pm 0.8\) & \(61.33\pm 2.3\) & \(13.16\pm 1.1\) & \(10.06\pm 0.9\) \\
2 & \(2.67\pm 0.26\) & \(0.142\pm 0.008\) & \(6.03\pm 0.88\) & \(70.13\pm 2.35\) & \(19.16\pm 0.9\) & \(62.07\pm 1.5\) & \(10.92\pm 0.7\) & \(9.75\pm 0.8\) \\
3 & \(1.90\pm 0.07\) & \(0.151\pm 0.009\) & \(9.32\pm 1.46\) & \(97.36\pm 1.67\) & \(30.68\pm 1.2\) & \(66.36\pm 2.1\) & \(12.38\pm 0.9\) & \(12.64\pm 1.1\) \\
4 & \(1.81\pm 0.07\) & \(0.174\pm 0.012\) & \(8.17\pm 0.74\) & \(88.96\pm 1.19\) & \(24.72\pm 1.0\) & \(65.35\pm 2.2\) & \(12.47\pm 1.2\) & \(11.01\pm 0.9\) \\
5 & \(2.64\pm 0.18\) & \(0.146\pm 0.028\) & \(6.85\pm 0.55\) & \(82.55\pm 1.19\) & \(22.77\pm 1.4\) & \(55.07\pm 1.1\) & \(13.22\pm 1.2\) & \(16.67\pm 1.2\) \\
6 & \(2.48\pm 0.05\) & \(0.132\pm 0.010\) & \(5.84\pm 1.06\) & \(78.32\pm 2.54\) & \(26.96\pm 0.8\) & \(56.53\pm 1.0\) & \(15.73\pm 1.1\) & \(15.16\pm 1.1\) \\
7 & \(1.59\pm 0.09\) & \(0.144\pm 0.015\) & \(8.36\pm 0.47\) & \(89.32\pm 2.67\) & \(24.43\pm 1.2\) & \(58.18\pm 1.1\) & \(15.18\pm 1.0\) & \(12.83\pm 1.0\) \\
8 & \(1.51\pm 0.01\) & \(0.186\pm 0.015\) & \(6.67\pm 1.45\) & \(93.56\pm 2.17\) & \(21.68\pm 1.5\) & \(58.87\pm 1.6\) & \(15.00\pm 0.9\) & \(13.89\pm 1.0\) \\ \hline \end{tabular}
\end{table}
Table 3: Experimental results for physical characteristics of extrudates.  
Figure 1: _Cont._  
Figure 1: Pareto charts for the effect of the factors on the physical and functional characteristics of extrudates.