## 3 Results and Discussion
### Influence of Ultrasound Time on Bioactive Extraction in Different Solvents  
In order to identify the conditions that allow us to obtain extracts with superior bioactive content while reducing the costs, the influence of the applied ultrasound treatment on the properties of the obtained extracts was further checked by varying the time interval from 5 to 20 min. Table 2 compares the phytochemical compositions of water and ethanol extracts after exposure to ultrasound treatment for up to 20 min, at a solid-to-liquid ratio of 1:100 (\(w/v\)). When water was used as a solvent, increasing the exposure time for UAE from \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Component**}} & \multicolumn{2}{c}{**Conventional**} & \multicolumn{3}{c}{**Ultrasound Amplitude, \%**} & \\  & **24 h, 25 \({}^{\circ}\)C** & **20** & **30** & **40** & **60** \\ \hline \multicolumn{1}{c}{Solvent: Water} & & & & & \\ \hline TPC mg GAE/g d.w. & 33.50 \(\pm\) 1.32 \({}^{\text{A}}\) & 27.38 \(\pm\) 1.46 \({}^{\text{Aa}}\) & 26.35 \(\pm\) 3.08 \({}^{\text{Aa}}\) & 33.03 \(\pm\) 3.15 \({}^{\text{Aa}}\) & 30.39 \(\pm\) 3.66 \({}^{\text{Aa}}\) \\ DPPH scavenging activity & 103.84 \(\pm\) 2.65 \({}^{\text{A}}\) & 73.10 \(\pm\) 0.11 \({}^{\text{b}}\) & 82.95 \(\pm\) 0.55 \({}^{\text{a}}\) & 80.84 \(\pm\) 1.76 \({}^{\text{a}}\) & 78.03 \(\pm\) 1.76 \({}^{\text{ab}}\) \\ mM Trolox/g d.w. & 163.03 \(\pm\) 0.43 \({}^{\text{A}}\) & 150.26 \(\pm\) 17.63 \({}^{\text{Ab}}\) & 228.41 \(\pm\) 10.32 \({}^{\text{a}}\) & 226.58 \(\pm\) 0.0 \({}^{\text{a}}\) & 228.41 \(\pm\) 12.9 \({}^{\text{a}}\) \\ \hline \multicolumn{1}{c}{Solvent: 70\% Ethanol} & & & & \\ \hline TPC mg GAE/g d.w. & 78.89 \(\pm\) 3.00 \({}^{\text{A}}\) & 72.15 \(\pm\) 1.39 \({}^{\text{Ac}}\) & 86.16 \(\pm\) 0.66 \({}^{\text{a}}\) & 73.60 \(\pm\) 1.39 \({}^{\text{Abc}}\) & 78.95 \(\pm\) 2.34 \({}^{\text{Ab}}\) \\ DPPH scavenging activity & 149.12 \(\pm\) 0.33 \({}^{\text{A}}\) & 149.59 \(\pm\) 0.77 \({}^{\text{Aa}}\) & 151.16 \(\pm\) 0.55 \({}^{\text{Aa}}\) & 149.91 \(\pm\) 0.77 \({}^{\text{Aa}}\) & 153.19 \(\pm\) 0.99 \({}^{\text{Aa}}\) \\ mM Trolox/g d.w. & 178.81 \(\pm\) 1.50 \({}^{\text{A}}\) & 348.81 \(\pm\) 8.6 \({}^{\text{a}}\) & 360.67 \(\pm\) 4.73 \({}^{\text{a}}\) & 360.67 \(\pm\) 3.87 \({}^{\text{a}}\) & 360.37 \(\pm\) 5.16 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The effects of the ultrasound amplitude at a maximum of 40 \({}^{\circ}\)C, for 10 min, on the recovery of bioactive compounds (total phenolic content—TPC) from BC pomace in different solvents. 5 to 20 min favored the release of bioactive compounds, increasing by about 49% for TPC and 54% for antioxidants as measured by the DPPH assay and by 65% for antioxidants as measured by the ABTS-based method. These results indicate that, with increasing time, water enhanced mass transfer, promoting extraction [7]. On the other hand, when using ethanol as a solvent, regardless of the phenolic compound tested, the time had no effect on the extraction. These results are associated with the solid-liquid ratio of 1:100 (\(w/v\)) used in this study and ethanol's ability to increase the extraction rate of antioxidants. Thus, when using 70% ethanol, the equilibrium state was reached in up to 5 min. Similar results were reported by [PERSON] et al. [33], where an ultrasound extraction time between 10 and 30 min (at ethanol concentrations ranging from 60 to 96%, with a solid-liquid ratio of 1:10) did not show a significant influence on bioactive recovery. To generate high extraction yields of antioxidants, the same authors recommended the use of ultrasound treatment for 20 min in BC samples containing 60% ethanol as a solvent. As shown in Table 1, UAE was able to produce similar or higher concentrations of antioxidants than conventional extraction. The extraction time of up to 20 min applied in our study generated similar total phenolic concentrations to those reported by [PERSON] et al.