## 3 Results and Discussion
### Effect of Ultrasound and Microwave Extraction on the Content of Bioactive Compounds
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Temp.** & **Extraction** & **Time** & **TPC (mg Gallic** & **TF (mg** & **TA (mg cyanidin-3-** \\
**(\({}^{\circ}\)C)** & **Type** & **(min)** & **Acid/g dm)** & **Quercetin/g dm)** \\ \hline \multirow{4}{*}{25} & water bath & 25 & 33.87 (0.11) \({}^{\text{ab}}\) & 5.13 (0.10) \({}^{\text{cd}}\) & 4.60 (0.02) \({}^{\text{bc}}\) \\ \cline{2-5}  & ultrasound & 5 & 34.15 (0.09) \({}^{\text{a}}\) & 5.16 (0.03) \({}^{\text{c}}\) & 4.68 (0.02) \({}^{\text{bc}}\) \\  & ultrasound & 25 & 34.18 (0.49) \({}^{\text{a}}\) & 5.26 (0.01) \({}^{\text{c}}\) & 5.11 (0.02) \({}^{\text{a}}\) \\  & & 45 & 34.12 (0.20) \({}^{\text{ab}}\) & 5.16 (0.01) \({}^{\text{c}}\) & 4.77 (0.03) \({}^{\text{e}}\) \\ \cline{2-5}  & microwave & 2 & 34.36 (0.19) \({}^{\text{a}}\) & 5.04 (0.12) \({}^{\text{cd}}\) & 5.09 (0.07) \({}^{\text{ab}}\) \\  & microwave & 3.16 & 34.22 (0.15) \({}^{\text{a}}\) & 5.10 (0.07) \({}^{\text{cd}}\) & 4.94 (0.12) \({}^{\text{ab}}\) \\  & & 4.33 & 33.42 (0.30) \({}^{\text{b}}\) & 4.92 (0.09) \({}^{\text{d}}\) & 4.83 (0.05) \({}^{\text{abc}}\) \\ \hline \multirow{4}{*}{45} & water bath & 25 & 35.26 (0.02) \({}^{\text{ab}}\) & 5.66 (0.08) \({}^{\text{b}}\) & 4.50 (0.03) \({}^{\text{cd}}\) \\  & ultrasound & 5 & 34.35 (0.09) \({}^{\text{c}}\) & 5.67 (0.12) \({}^{\text{b}}\) & 4.24 (0.05) \({}^{\text{de}}\) \\  & ultrasound & 25 & 35.95 (0.06) \({}^{\text{a}}\) & 6.03 (0.02) \({}^{\text{a}}\) & 4.05 (0.18) \({}^{\text{e}}\) \\  & & 45 & 35.76 (0.07) \({}^{\text{a}}\) & 6.04 (0.09) \({}^{\text{a}}\) & 4.01 (0.03) \({}^{\text{e}}\) \\ \cline{2-5}  & microwave & 2 & 34.26 (0.30) \({}^{\text{c}}\) & 5.15 (0.07) \({}^{\text{c}}\) & 4.92 (0.13) \({}^{\text{ab}}\) \\  & microwave & 3.16 & 35.33 (0.11) \({}^{\text{ab}}\) & 5.19 (0.06) \({}^{\text{c}}\) & 4.88 (0.10) \({}^{\text{abc}}\) \\  & & 4.33 & 34.52 (0.77) \({}^{\text{bc}}\) & 5.22 (0.08) \({}^{\text{c}}\) & 4.72 (0.33) \({}^{\text{abc}}\) \\ \hline \multicolumn{2}{c}{Extraction type} & NS & *** & *** \\ \hline \multicolumn{2}{c}{Temperature} & *** & *** \\ \hline \multicolumn{2}{c}{Extraction type \(\times\)Temperature} & NS & *** & *** \\ \hline \hline \end{tabular}  
* a, b, c, d, e\({}^{\text{a}}\) means with different small superscript letters differ significantly for samples of the same extract at different temperatures. NS—not significant; ***—significant at \(p\leq 0.001\).  
\end{table} 
Table 2: Total phenol (TPC), total flavonoid (TF) and total anthocyanin (TA) contents in acai extracts obtained using water baths, ultrasound and microwaves at different times and temperatures. Factorial analysis of the impact of extraction type, temperature and extraction type \(\times\) temperature on TPC, TF and TA. The results are presented as means (SD, standard deviation). that microwaves offer a more time-efficient method. Microwave extraction at 45 \({}^{\circ}\)C carried out for up to 3.16 min significantly increased the amount of extracted TA in comparison to the ultrasound method. At lower temperatures, a difference was not detected. [PERSON] (2018) reported that extraction carried out using microwaves for longer than 5 min and at a temperature above 50 \({}^{\circ}\)C caused a decrease in the anthocyanin content in the extract. A similar effect was obtained in the experiment, where the anthocyanin content decreased with increasing temperature. This is related to the high thermal stability of anthocyanins and their degradation at higher temperatures ([PERSON], 2017). Extraction type, temperature and extraction type \(\times\) temperature had an influence (\(p\leq 0.001\)) on the content of flavonoids and anthocyanins in the analyzed extracts, whereas, in the case of total phenolic compounds, only temperature was statistically significant (\(p\leq 0.001\)).