## 3 Results and Discussion
### Thermal Properties of Fruit Fibres and Pomace
\begin{table}
\begin{tabular}{c c c c} \hline  & \multicolumn{3}{c}{**Pomace**} \\ \cline{2-4}  & **Chokeberry** & **Apple** & **Currant** \\ \hline \multirow{4}{*}{**Equation coefficient**} & \(u_{m}=0.072\) & \(u_{m}=0.065\) & \(u_{m}=0.059\) \\ \cline{2-4}  & \(C=2489.925\) & \(C=589.143\) & \(C=1.362\) \\ \cline{2-4}  & \(k=0.723\) & \(k=0.772\) & \(k=0.744\) \\ \hline \(R^{2}\) & 0.983 & 0.996 & 0.976 \\ \hline \multicolumn{4}{c}{_MRE(\%)_} & 3.354 & 2.156 & 4.409 \\ \hline \multicolumn{4}{c}{_RMS_} & 4.201 & 3.293 & 5.272 \\ \hline \multicolumn{4}{c}{_RSS_} & 0.030 & 0.017 & 0.049 \\ \hline \multicolumn{4}{c}{_SEE_} & 0.173 & 0.131 & 0.221 \\ \hline \end{tabular}
\end{table} 
Table 7: _Cont._degradation temperatures, ranging from 418.42 to 430.22 \({}^{\circ}\)C. However, the weight loss in the case of chokeberry pomace was 15.19%, and in the case of currant pomace and apple pomace, from 7.89 to 10.03%. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**1 st Stage**} & \multicolumn{2}{c}{**2 nd Stage**} & \multicolumn{2}{c}{**3 rd Stage**} & \multicolumn{2}{c}{**4 th Stage**} \\  & **30.00–130.00 \({}^{\circ}\)C** & **130.00–310.00 \({}^{\circ}\)C** & **310.00–380.00 \({}^{\circ}\)C** & **380.00–600.00 \({}^{\circ}\)C** \\ \cline{2-7}
**Sample** & \multirow{2}{*}{**T (\({}^{\circ}\))**} & **Weight** & \multirow{2}{*}{**T (\({}^{\circ}\))**} & **Weight** & \multirow{2}{*}{**T (\({}^{\circ}\))**} & **Weight** & \multirow{2}{*}{**T (\({}^{\circ}\))**} & **Weight** \\  & & **Loss (\%)** & & **Loss (\%)** & & **Loss (\%)** & & **Loss (\%)** \\ \hline
**apple fibre** & 66.88 & 5.21 & 243.36 & 29.89 & 344.74 & 9.89 & 422.23 & 5.10 \\
**currant fibre** & 64.31 & 6.65 & 242.88 & 19.56 & 340.07 & 10.19 & 428.17 & 12.17 \\
**chokeberry fibre** & 65.95 & 6.15 & 287.33 & 13.36 & 348.58 & 5.61 & 425.23 & 12.31 \\
**apple pomace** & 67.32 & 3.89 & 242.45 & 24.31 & 346.80 & 4.76 & 430.22 & 10.03 \\
**currant pomace** & 66.95 & 6.03 & 239.72 & 18.59 & 343.32 & 7.82 & 425.76 & 7.89 \\
**chokeberry pomace** & 66.54 & 6.14 & 288.30 & 14.25 & 353.96 & 4.21 & 418.42 & 15.19 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Temperature and weight loss related to the stages of TG/DTG curves of fruit fibre and pomace from apple, currant and chokeberry. Figure 6: The thermogravimetric analysis (TGA) (red) and derivative thermogravimetry (dTG) (yellow) of the selected fruit fibres. Similar results of thermal analysis of pomace were obtained by [PERSON] et al. [33]. Apple pomace showed an initial weight loss (1.00 to 4.00%) at temperatures of 70.00-12.00 \({}^{\circ}\)C. The second degradation stage (193.00-400.00 \({}^{\circ}\)C) had a significant weight loss (up to 65.00%) due to the degradation of polysaccharides and lipids and strong reactions such as dehydro-droxylation, deoxygenation or decarboxylation. The third stage (400.00-700.00 \({}^{\circ}\)C) resulted in complete weight loss attributed to the degradation of cellulose or the degradation of substances resulting from the polymerisation of degradation products produced in the earlier stages. Also, in the study by [PERSON] et al. [34], characteristic peaks were observed for pectorins and hemicelluloses with maxima ranging from 186.00 to 215.00 \({}^{\circ}\)C and 235.00 to 237.00 \({}^{\circ}\)C, respectively. Weight loss over this temperature range ranged from 18.00 to 23.00%. In the study by [PERSON] et al. [35], weight loss was not significant below 150.00 \({}^{\circ}\)C, and the first weight loss was evident between 150.00 and 200.00 \({}^{\circ}\)C. This weight change was due to moisture loss and other volatile components, such as oils, pigments. The second weight loss could be observed between 250.00 and 400.00 \({}^{\circ}\)C and corresponded to the degradation of cellulose and hemicelluloses. The weight loss was not significant after 700.00 \({}^{\circ}\)C.