## 3 Results and Discussion
### The Antioxidant Activity  
The antioxidant activity of obtained extracts ranged from 11.5 to 21.3 \(\times\) 10\({}^{-6}\) MTE/1 g (DM) while tested by use of the DPPH method and from 16.9 to 29.7 \(\times\) 10\({}^{-6}\) MTE/1 g (DM) using the FRAP method, varying according to the experimental conditions. The obtained antioxidant activity is more than 100 times lower than the antioxidant activity of the extract from _Iuglans regia_ L. flowers. The antioxidant activity of the extract obtained from _Iuglans regia_ L. flowers was 3.33 \(\times\) 10\({}^{-3}\) MTE/1 g (DM) [39]. Antioxidant activities as a function of extraction temperatures are presented in Figure 4. \begin{table}
\begin{tabular}{l r r r r r r} \hline \hline  & \multicolumn{1}{c}{**Sum of**} & \multicolumn{1}{c}{**df**} & \multicolumn{2}{c}{**Mean**} & \multicolumn{1}{c}{**F-Value**} & \multicolumn{1}{c}{_p-Value_} & \\  & \multicolumn{1}{c}{**Squares**} & \multicolumn{1}{c}{**df**} & \multicolumn{1}{c}{**Square**} & \multicolumn{1}{c}{**F-Value**} & \multicolumn{1}{c}{_p-Value_} & \\ \hline Model & 4571.42 & 5 & 914.28 & 162.42 & \textless{}0.0001 & significant \\ A—Temperature & 2545.16 & 1 & 2545.16 & 452.14 & \textless{}0.0001 & \\ B—Fraction size & 203.00 & 1 & 203.00 & 36.06 & 0.0002 & \\ C—Process time & 381.85 & 1 & 381.85 & 67.83 & \textless{}0.0001 & \\ AC & 148.63 & 1 & 148.63 & 26.40 & 0.0006 & \\ A\({}^{2}\)—Temperature\({}^{2}\) & 1292.78 & 1 & 1292.78 & 229.66 & \textless{}0.0001 & \\ Residual & 50.66 & 9 & 5.63 & & & \\ \hline Lack of Fit & 25.21 & 7 & 3.60 & 0.2831 & 0.9130 & not significant \\ \hline Pure Error & 25.45 & 2 & 12.72 & & & \\ \hline Cor Total & 4622.09 & 14 & & & \\ \hline Std. Dev. = 2.37; Mean = 67.39; C.V. \% = 3.52; R\({}^{2}\) = 0.9890; Adjusted R\({}^{2}\) = 0.9829; & Predicted R\({}^{2}\) = 0.9744; Adeq Precision = 40.9157 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The analysis of variance for total flavonoids. Multivariable analysis of variance (ANOVA) performed with use of the results of antioxidant activity assessment using DPPH and FRAP methods shows that the antioxidant activity is strictly dependent on the temperature only. The influence of temperature mentioned above can be represented by a second-order equation. With the DPPH method, antioxidant activity increases with an increasing temperature value up to 131.6 \({}^{\circ}\)C and then decreases, whereas with the FRAP method the maximum point was observed at 134.7 \({}^{\circ}\)C. Details of ANOVA analysis are presented in Table 7 for the DPPH method and Table 8 for the FRAP method. The F-value of 14.66 indicates that the model is significant. There is only a 0.06% chance that an F-value this large could occur due to noise. \(p\)-values less than 0.05 indicate significance of the model terms. Significant model terms are A and A\({}^{2}\). The lack of fit F-value of 2.23 implies the lack of fit is not significant relative to the pure error. The predicted R\({}^{2}\) (0.5762) and adjusted R\({}^{2}\) (0.6611) are in reasonable agreement. The signal-to-noise ratio is referred as Adeq Precision. A ratio of 7.516 indicates an adequate signal. The obtained model is statistically significant and can be used to navigate the analyzed space.