3.2. Ferric reducing antioxidant power (FRAP)
In this assay sample readings were referenced to the standard curve of ferrous sulphate, FeSO4_H2O. The FRAP value was expressed as mmol Fe2+/g sample. shows the reductive capability of WTE. The FRAP value of the sample in hot water extractions was 1.6 } 0.044 mmol Fe2+/g and the FRAP values for the controls, catechin, quercetin and rutin, were 6.5 } 0.004 , 7.5 } 0.035 and 3.03 } 0.028 mmol Fe2+/g, respectively. Since the positive controls, catechin, quercetin and rutin, used were pure compounds, it is expected that they would have higher FRAP values. Pearson correlation analysis was performed to assess the relationship between the phenolic content of the extract and ferric reducing activity. There was a strong positive correlation between the TPC of WTE and FRAP value (r = 0.902).