## 3 Results
### UAE Parameters Influence on the TPC, TFC and TAA  
The ultrasound-assisted extraction experiments were performed at a constant temperature (40 \({}^{\circ}\)C) with a 60% hydroalcoholic solution, (\(v/v\)) considering three independent variables (Table 3) in order to find the optimal extraction conditions to maximize the TPC, TFC and TAA concentrations. The three-level, three-factor Box-Behnken design was used to study the effect of the independent variables (\(\chi_{1}\)--amplitude, \(\chi_{2}\)--sonication mode, \(\chi_{3}\)--time). The amplitude term refers to the amplitude of oscillation generated by the probe. In our experiments, the maximum amplitude of oscillation of the titanium probe was 79 \(\upmu\)m (100%, Table 3). The central point of the experimental design was performed in triplicate at the conditions 60% amplitude, 10 min, and 0.75 sonication mode (U13-U15, Table 3). The results obtained at the three replicates of this central point presented some differences among them due to the possibility of the temperature increasing during sonication. Furthermore, at higher amplitudes higher accelerations were generated, which increased the probability of cavitation  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Run Order**} & \multicolumn{3}{c}{**Independent Variables**} & \multicolumn{3}{c}{**Response Variables**} & **Energy** \\ \cline{2-7}  & **Amplitude** & **Sonication** & **t** & **TPC** & **TFC** & **TAA** & **Delivered** \\  & **(\%)** & **Mode (\(\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{ \boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{ \boldsymbol{\boldsymbol{ \boldsymbol{ \boldsymbol{ }}}}}}}}}}}}}\) & **(\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{ \boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{ \boldsymbol{\boldsymbol{\boldsymbol{\boldsymbol{ \boldsymbol{\boldsymbol{ \boldsymbolboldsymbol{ \boldsymbolboldsymbol{ \boldsymbol  
phenomena due to the higher-pressure differences. Increased cavitation leads to higher extraction rates. At the same amplitude (60%), if the extraction time decreased down to 5 min, but with continuous sonication action, the TPC value was 32.42 \(\pm\) 1.13 mg GAE/g dw (U10). At the maximum ultrasound amplitude and continuous sonication (run U17), the TPC concentration (31.44 \(\pm\) 0.49 mg GAE/g dw) was close to the result obtained at 60% amplitude (U10). This means that the amplitude during ultrasound extraction had no effect on the recovery of the TPC concentration. Our results are in accordance with [PERSON] et al. [28] who obtained no amplitude influence on the recovery of total phenols from brown seaweed _Ascophylum nodosum_. Moreover, [PERSON] et al. [29] concluded that the amplitude in the range of 50-100% had no significant effect on the extraction yields of the individual and total glycoalkaloids of potato peel. In Table 4, it can be observed that the fitting of the UAE experiments is poor; the independent variables do not affect the responses studied. According to the literature, the UAE performance may be quantified by some variables, such as the solid/liquid (S/L) ratio, temperature, and ultrasound amplitude [30; 33; 34; 35; 36; 37; 38]. Other authors report that suboptimal UAE conditions may lead to reduced cavitation phenomena, resulting in reduced recovery bioactives [39]. [PERSON] et al. [15] reported the highest TPC concentration (>25 mg GAE/g dw) after 15 min of UAE with a hydroalcoholic solution and an ethanol concentration between 50-70%. [PERSON] and [PERSON] [40] obtained cornelian cherry extracts with 10% methanol (\(v/v\)) and 1% hydrochloric acid (\(v/v\)) at 30 \({}^{\circ}\)C during 60 min in a water bath with ultrasound.