## 3 Results and Discussion
### Comparison among the Soxhlet, Percolation, and Thermosonication Techniques
The extract obtained by thermosonication also presented higher antioxidant activity than the extract acquired by percolation when measured by TEAC. However, an opposite behavior was verified by the DPPH results. Other studies have reported these discrepancies in antioxidant activity [27]. Despite this, the TEAC results seem to be more consistent in our study since the extract obtained by thermosonication showed a higher phenolic compounds' content than the acquired by percolation. Figure 6: TPC yield acquired for each extraction technique. Although the Soxhlet technique produced an extract with the highest content of phenolic compounds and antioxidant capacity, it employed more electrical energy than percolation and thermosonication techniques. Table 3 presents the electricity consumption for obtaining fennel extracts by each extraction method. The cost of electrical energy to carry out thermosonication was the lowest to obtain the ethanolic extract, dry solids, and phenolic compounds of fennel. After thermosonication, percolation required less electrical energy than the Soxhlet technique. The main difference in the energy cost for carrying out the extractions is the time used by each technique. Soxhlet and percolation extractions were performed for 6 h. In contrast, thermosonication was carried out in about 20 min. Additionally, the highest difference in energy expenditure was in total electricity consumption related to the extraction of phenolics compounds (Figure 8c). Figure 8 presents the electrical energy cost in dollars to obtain the extract, dried solids, and phenolic compounds of the fennel by each extraction method. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{2}{c}{**Extraction Parameters**} & \multicolumn{2}{c}{**Electricity Consumption**} & \multicolumn{2}{c}{**Total Electricity Consumption**} & \multicolumn{2}{c}{**Total Electricity Consumption**} & \multicolumn{2}{c}{**Total Electricity Consumption**} \\ \multicolumn{2}{c}{**Technique**} & **Equipment** & **Time (h)** & **(kWh)/kg extract** & **(kWh/kg extract)** & **(kWh/kg extract)** & **(kWh/kg extract)** \\ \hline \multirow{4}{*}{Soxhlet} & Warming blanket & \multirow{4}{*}{6} & \multirow{4}{*}{1.98} & \multirow{4}{*}{9096} & \multirow{4}{*}{353,094} \\  & (Fisatom, 330 W) & & & & & \\ \cline{2-2} \cline{5-6}  & Water & \multirow{4}{*}{6} & \multirow{4}{*}{10.8} & \multirow{4}{*}{7.2} & \multirow{4}{*}{47} & \multirow{4}{*}{4817} \\  & recirculation & & & & & \\ \cline{2-2} \cline{5-6}  & system (Marconi, & 1800 W) & & & & \\ \hline \multirow{4}{*}{Percolation} & Shaker incubator & \multirow{4}{*}{6} & \multirow{4}{*}{7.2} & \multirow{4}{*}{47} & \multirow{4}{*}{4817} & \multirow{4}{*}{156,241} \\  & with orbital & & & & & \\ \cline{1-1} \cline{3-4} \cline{6-6}  & shaking and & \multirow{4}{*}{6} & \multirow{4}{*}{7.2} & \multirow{4}{*}{47} & \multirow{4}{*}{4817} & \multirow{4}{*}{156,241} \\  & heating (Marconi, & 1200 W) & & & & \\ \hline \multirow{4}{*}{Thermosonication (300 W, 60 \({}^{\circ}\)C)} & Ultrasound & \multirow{4}{*}{0.25} & \multirow{4}{*}{0.075} & \multirow{4}{*}{16} & \multirow{4}{*}{2127} & \multirow{4}{*}{42,276} \\  & heating water & \multirow{4}{*}{0.32} & \multirow{4}{*}{0.16} & \multirow{4}{*}{16} & \multirow{4}{*}{2127} & \multirow{4}{*}{42,276} \\  & bath (Marconi, & 500 W) & & & & \\ \hline \hline \end{tabular} The cost of ethanol evaporation to obtain the dried solids extracted and total phenolic compounds was not considered.  
\end{table} 
Table 3: Electricity consumption to obtain fennel extract, dried fennel solids, and fennel total phenolics. Figure 7: Antioxidant capacity of extracts acquired by each extraction method using (**a**) DPPH and (**b**) ABTS as chromophore radicals. The cost to extract the phenolic compounds from fennel by thermosonication was approximately 50 times lower than by percolation and Soxhlet processes.