# The Effect of Hydrolysis on the Antioxidant Activity of Olive Mill Waste
## 3 Results
### Correlation Analysis
#### 3.3.2 Correlation between TPC, TFC and TdOPC with Metal Ion Reducing Assays (FRAP and CUPRAC)
The \(\rho\)-value of methanolic extracts (\(\blacksquare\)) was 0.78, for acidic hydrolysis (+) it was 0.80 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.76. (**B**) Correlation between TFC and FRAP. The \(\rho\)-value of methanolic extracts (\(\blacksquare\)) was 0.45, for acidic hydrolysis (+) it was 0.45 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.052. (**C**) Correlation between TdOPC and FRAP. The \(\rho\)-value of methanolic extracts was 0.46, for acidic hydrolysis (+) it was 0.06 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.25. (**D**) Correlation between TPC and CUPRAC. The \(\rho\)-value of methanolic extracts (\(\blacksquare\)) was 0.69, for acidic hydrolysis (+) it was 0.57 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.93. (**E**) Correlation between TFC and CUPRAC. The \(\rho\)-value of methanolic extracts (\(\blacksquare\)) was 0.84, for acidic hydrolysis (+) it was 0.48 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.63. (**F**) Correlation between TdOPC and CUPRAC. The \(\rho\)-value of methanolic extracts was 0.83, for acidic hydrolysis (+) it was 0.58 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.69. Figure 9: (**A**) Correlation between TPC and TFC. The \(\rho\)-value of methanolic extracts (\(\blacksquare\)) was 0.67, for acidic hydrolysis (+) it was \(-\)0.09 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.51. (**B**) Correlation between TPC and TdOPC. The \(\rho\)-value of methanolic extracts (\(\blacksquare\)) was 0.23 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.57. (**C**) Correlation between TPC and TdOPC. The \(\rho\)-value of methanolic extracts was 0.95, for acidic hydrolysis (+) it was 0.77 and for alkaline hydrolysis (\(\blacktriangle\)) it was 0.96. 3.3 Correlation between \(ABTS\) and \(DPPH\) Radical Scavenging Activity with TPC, TFC and TdOPC  
The correlation of different phenolic classes with \(DPPH\) and \(ABTS\) showed a significant negative correlation with TPC in all extraction procedures (\(DPPH\): macerated-\(\rho=-0.73\), alkaline-\(\rho=-0.47\) and acid-\(\rho=-0.50\) and \(ABTS\): macerated-\(\rho=-0.70\), alkaline-\(\rho=-0.57\) and acid-\(\rho=-0.47\)). Furthermore, it was also found that \(DPPH\) in macerated extracts had a significant negative correlation with TFC, with a \(\rho\)-value of \(-0.46\), whereas for the hydrolysed extracts, there was no correlation observed. For \(ABTS\), all extractions significantly negatively correlated with TPC (macerated-\(\rho=-0.77\), acid-\(\rho=-0.21\), alkaline-\(\rho=-0.67\)). Only macerated extracts showed a significant negative correlation between \(DPPH\) and TdOPC (\(\rho=-0.43\)), whereas in the hydrolysed extracts, no correlation was observed. \(ABTS\) negatively correlated with TdOPC for all extraction procedures used (macerated-\(\rho=-0.73\), alkaline-\(\rho=-0.70\), acid-\(\rho=-0.26\)). 3.4 Correlation between Hydrogen Peroxide and Superoxide Scavenging Activity with TPC, TFC and TdOPC  
Figure 11 shows the correlation of hydrogen peroxide scavenging activity with TPC, TFC and TdOPC. It was found that hydrogen peroxide significantly positively correlated with TPC and TdOPC in all extraction procedures (TPC: macerated-\(\rho=0.42\), acid--0.80 and alkaline-\(\rho=0.85\) and TdOPC: macerated-\(\rho=0.46\), acid-\(\rho=0.18\), alkaline-\(\rho=0.58\)). Hydrogen peroxide scavenging activity in macerated and alkaline hydrolysed extracts also significantly positively correlated with TPC (\(\rho=0.45\) and \(0.55\)), whereas for acid hydrolysed extracts, no correlations were observed. _Superoxide Scavenging_ activity was found to be correlated only with TPC in methanolic extracts, whilst there was no significant correlation observed for hydrolysed extracts.