## 3 Results and Discussion
### Statistical Correlations  
Blackberries contain many phytochemicals, and to elucidate which components are responsible for the main antioxidant effect, we examined whether the data were normally distributed, and then, we applied the Pearson correlation between the antioxidant capacity and the total anthocyanins, flavonoids, and polyphenols. Table 3 shows that, in all cases, the distribution is normal, the values obtained for the Z-test fall within the 95% confidence interval (\(-1.96\); \(+1.96\)), and both the Kolmogorov-Smirnov and Shapiro-Wilk tests also show that the distribution is normal at \(p=0.05\) significance level. Since the distribution is normal, the Pearson correlation could be applied. In Table 4, the Pearson correlation analysis results are summarized. The result shows that there is a significant positive correlation between DPPH radical scavenging activity  
Figure 4: FRAP assay of blackberries extracts in mg AAE/g DW. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**N = 12** & **TAC** & **TPC** & **TFC** & **DPPH Assay** & **FRAP Assay** \\ \hline Skewness & \(-0.3\) & \(-0.682\) & \(0.211\) & \(-0.669\) & \(-0.158\) \\ Standard error & \(0.637\) & \(0.637\) & \(0.637\) & \(0.637\) & \(0.637\) \\ \(Z\) test & & & & & \\ \(z=\frac{\text{Skewness}}{\text{Standard error}}\) & \(-1.459\) & \(-1.07\) & \(0.331\) & \(-1.05\) & \(-0.248\) \\ Kurtosis & \(-1.049\) & \(-0.294\) & \(-1.176\) & \(-1.050\) & \(-0.769\) \\ Standard error & \(1.232\) & \(1.232\) & \(1.232\) & \(1.232\) & \(1.232\) \\ \(Z\) test & & \(-1.292\) & \(-0.238\) & \(-0.954\) & \(-0.852\) & \(-0.624\) \\ \(z=\frac{\text{Kurtosis}}{\text{Standard error}}\) & & & & & \\ \(\text{Kolmogorov-Smirnov}\) & Statistics & \(0.105\) & \(0.162\) & \(0.123\) & \(0.177\) & \(0.172\) \\  & Significance & \(0.200\) & \(0.200\) & \(0.200\) & \(0.200\) & \(0.200\) \\ Shapiro-Wilk & Statistics & \(0.956\) & \(0.947\) & \(0.959\) & \(0.883\) & \(0.951\) \\  & Significance & \(0.850\) & \(0.592\) & \(0.769\) & \(0.096\) & \(0.648\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The normality testing results of the measurement error distribution. and total polyphenol content (r = 0.95; \(p<0.01\)), a similar correlation has been reported in the literature [23; 28; 37; 43; 44]. Furthermore, it was shown that DPPH stable radicals are mainly able to be reduced by more reactive components than polyphenolic compounds. They are the main components responsible for the high antioxidant capacity of the extracts. This trend is also characteristic of the FRAP method (r = 0.836; \(p<0.01\)), as pointed out by other authors such as [PERSON] et al., by the polyphenol's Fe\({}^{3+}\) ion reducing ability [42]. The correlation between total anthocyanins-total flavonoids, as well as between the DPPH-FRAP results are also significant. Still, the correlations are looser in comparison to the radical scavenging activity-total polyphenol content, indicating that anthocyanins and flavonoids are only moderately responsible for the antioxidant effect: a phenomenon that has been observed by other researchers [28; 42]. Using linear regression in Microsoft Excel, the Figure 5 graphically illustrates the positive linear correlation between total polyphenol content and the DPPH scavenging activity of the extracts (R\({}^{2}\) = 0.9026). \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & **TAC** & **TPC** & **TFC** & **DPPH Assay** & **FRAP-Assay** \\ \hline DPPH radical scavenging activity & Pearson correlation & 0.614 ** & 0.950 ** & 0.630 * & 1 & 0.903 ** \\ Significance level (2-tailed) & 0.004 & 0.000 & 0.028 & - & 0.000 \\ N & 12 & 12 & 12 & 12 & 12 \\ \hline \multirow{3}{*}{FRAP-assay} & Pearson correlation & 0.491 & 0.836 ** & 0.732 ** & 0.903 ** & 1 \\  & Significance level (2-tailed) & 0.065 & 0.001 & 0.007 & 0.000 & - \\ N & 12 & 12 & 12 & 12 & 12 \\ \hline \end{tabular}  
* The correlation is significant at 0.05 significance level (2-tailed). ** The correlation is significant at 0.01 significance level (2-tailed).  
\end{table}