## 3 Results and Discussion
### Optimization of UAE of the Antioxidant Bioactive Compounds
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**RP**} & \multicolumn{4}{c}{**WP**} \\ \hline  & \multicolumn{2}{c}{**TPC**} & \multicolumn{2}{c}{**FRAP**} & \multicolumn{2}{c}{**TPC**} & \multicolumn{2}{c}{**FRAP**} \\ \hline  & \multicolumn{2}{c}{**Regression**} & \multicolumn{2}{c}{**F-Ratio**} & \multicolumn{2}{c}{**Regression**} & \multicolumn{2}{c}{**Regression**} & \multicolumn{2}{c}{**F-Ratio**} & \multicolumn{2}{c}{**Regression**} & \multicolumn{2}{c}{**F-Ratio**} \\  & **Coefficients** & & **Coefficients** & & **Coefficients** & & **Coefficients** & & **Coefficients** & & \\ \hline Constant & 14.8945 & – & 17.2539 & – & 52.3174 & – & 56.3087 & – \\ A: Ratio & 0.0945833 & 1.06 & 1.56819 & 39.97 * & – & \(-\)0.4568 & 7.38 & 2.41467 & 7.96 * \\ B: Amplitude & \(-\)0.163824 & 70.45 * & 0.437697 & 29.98 * & \(-\)0.266311 & 57.75 * & \(-\)0.799285 & 48.28 * \\ C: Time & 1.05176 & 0.57 & 1.60485 & 0.01 & \(-\)1.83954 & 0.53 & \(-\)2.24923 & 0.25 \\ AA & \(-\)0.0212917 & 25.13 * & \(-\)0.0409677 & 19.94 * & \(-\)0.00506735 & 1.49 & \(-\)0.0542652 & 31.53 * \\ AB & 0.0102042 & 3.52 & 0.00626667 & 0.28 & 0.00907594 & 2.91 & \(-\)0.0061721 & 0.25 \\ AC & 0.049625 & 20.80 * & 0.0869333 & 13.68 * & 0.0217452 & 4.17 & 0.0780597 & 9.94 * \\ BB & 0.00526481 & 0.49 & \(-\)0.00734259 & 0.20 & 0.00019970 & 0.00 & 0.0251357 & 2.14 \\ BC & 0.0137333 & 0.90 & 0.0371111 & 1.40 & 0.0317853 & 5.01 & 0.0539508 & 2.67 \\ CC & \(-\)0.0790741 & 6.85 & \(-\)0.145904 & 5.00 & 0.0143494 & 0.24 & \(-\)0.0361915 & 0.28 \\ \hline \multicolumn{8}{c}{* \(p<0.05\).} \\ \end{tabular}
\end{table} 
Table 2: Regression coefficients and F-ratios of the predicted second-order polynomial models for TPC and FRAP obtained from the RP and the WP. (\(p>0.05\)), indicating that the model possesses a reliable predictive capacity and fits the experimental data. Figures 3 and 4 show that when amplitude increases up to 40%, the bioactivity steadily increases. At high amplitudes, an important release of phenolic compounds occurs; however, the extraction yield reduces after a given peak, beyond which points polyphenols are destroyed [41; 48; 49]. Another previous study also showed that polyphenols can be damaged at amplitudes greater than 40% [50]. However, the optimal amplitude depends on the matrix and the stability of its antioxidant molecules. The amplitude at which the highest FRAP was obtained was 80% for fortified _Baulinha_[51], 90% for sugar beet molasses [52], 50% for pomegranate [53] and 30% for area nuts [54]. Another important determinant of the FRAP is the solute/solvent ratio, which was optimal at 1:37 and 1:45 for the RP and the WP, respectively. Increases in the TPC and FRAP with a decrease in the solid/solvent ratio correspond to an increase in the yield of polyphenols, probably due to better swelling of the solute powder, which favors the cavitation process and causes cell wall rupture and more efficient mass transfer during UAE [55; 56; 57; 58]. Previous research has determined that the extraction yields of polyphenolic compounds for different materials depend on the properties and structure of the compounds, the degree of polymerization and its relationship with the polarity of the solvent used for extraction [59]. Figure 4: The response surface for TPC (**a**) and FRAP (**b**) when using UAE on WP. In all cases, the third variable (C = time) is taken as the mean value. Figure 3: The response surface for TPC (**a**) and FRAP (**b**) when using UAE on RP. In all cases, the third variable (C = time) is taken as the mean value.