## 3 Results  
### Chemical Properties of Ultrasound- and Thermal-Treated Samples  
#### 3.1.1 Total Protein Content  
Regardless of the chosen extraction method, samples prepared with fresh sugar beet leaves (LUWI, LUWW, and LW0) have shown a higher yield of total proteins compared to samples prepared with dried leaves (LUDI, LUDW, and LD0) as presented in Tables 3 and 4. The higher yield of total proteins was observed in dry ultrasound-treated samples (Table 3), compared to thermal-treated samples (Table 5). The exceptions were samples LUDW7 and LUDI3, where the obtained yields were slightly lower than the yields of the thermal-treated samples. The highest yield of total proteins was observed in the sample LUDI6 (Table 3), where with the application of an amplitude of 100% and with a treatment time of 9 min, the yield was 107.20 \(\pm\) 9.23 mg(g\({}_{\rm d.m.}\))\({}^{-1}\). The obtained result was 1.44 to 1.64 times higher compared to thermal-treated samples. In terms of sustainability, the aforementioned increase is not negligible and insignificant, especially if consumption of energy is included in that mutual relationship, which was significantly higher in thermal-treated samples. A similar trend was observed in samples of fresh sugar beet leaves. Specifically, in the case of the LUWW6 sample (147.91 \(\pm\) 4.58 mg(g\({}_{\rm d.m. }\))\({}^{-1}\)), where an increase in total protein yield was observed by 1.91-2.02% compared to the thermally treated samples. In the case of LUWI and LUWW samples, optimization resulted in optimal values of amplitude of 100% and treatment time of 9 min. The mentioned input parameters (Table 6) have a statistically significant effect on the yield of total proteins in samples with fresh sugar beet leaves (\(p<0.05\)). The samples with dry sugar beet leaves (Table 7), in addition to the mentioned input variables, are also affected by their mutual interaction and the square interaction of time (LUDI and LUDW samples) and the square interaction of amplitude (LUDI), \(p<0.05\). The treatment time showed a statistically significant influence on the yield of total proteins in LD0 and LW0 samples (Table 8). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Source**} & \multicolumn{6}{c}{**Main Effects**} & \multicolumn{6}{c}{**Interactions**} \\ \cline{2-11}  & \multicolumn{2}{c}{**A: Amplitude**} & \multicolumn{2}{c}{**B: Treatment Time**} & \multicolumn{2}{c}{**AA**} & \multicolumn{2}{c}{**AB**} & \multicolumn{2}{c}{**BB**} \\ \hline \hline \multirow{5}{*}{_P_} & **LUWI** & **LUWW** & **LUWI** & **LUWW** & **LUWI** & **LUWW** & **LUWI** & **LUWW** & **LUWI** & **LUWW** & **LUWI** & **LUWW** \\ \hline \multirow{5}{*}{_P_} & pH & 0.45 & 0.09 & **0.02** & 0.35 & 0.54 & 0.14 & 0.09 & 0.27 & **0.03** & 0.34 \\ \cline{2-11}  & Conductivity & **0.00** & **0.00** & **0.00** & **0.01** & 0.06 & 0.79 & 0.55 & 0.23 & 0.13 & 0.12 \\ \cline{2-11}  & Energy & **0.00** & **0.00** & **0.00** & **0.00** & 0.13 & 0.25 & **0.00** & **0.00** & 0.06 & 0.31 \\ \cline{2-11}  & CO\({}_{2}\) emission & **0.00** & **0.00** & **0.00** & 0.13 & 0.25 & **0.00** & **0.00** & 0.06 & 0.31 \\ \cline{2-11}  & Total power & **0.02** & **0.00** & 0.16 & **0.01** & 0.83 & 0.38 & 0.51 & 0.75 & 0.72 & 0.27 \\ \cline{2-11}  & Total proteins & **0.01** & **0.01** & **0.02** & **0.02** & 0.11 & 0.27 & 0.54 & 0.35 & 0.22 & **0.41** \\ \cline{2-11}  & Total phenols & **0.01** & **0.01** & **0.03** & 0.06 & 0.71 & 0.69 & 0.58 & 0.46 & 0.75 & 0.77 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Statistical significance for pH, conductivity, energy, CO\({}_{2}\) emission, power, total proteins, and total phenols. MANOVA statistically processes the variability of each input parameter, their mutual interactions, and quadratic interactions on the output values of LUWI and LUWW samples.