Blanching effect of Cleome gynandra leaves on antioxidant properties

There is less information about the effect of blanching time specifically on Cleome gynandra plant. Thus, this study was conducted to study the effect of blanching time on the leaves of Cleome gynandra at 2 min, 5 min, 10 min, and 15 min. Leaves were dried, extracted and proceed for antioxidant activities analysis and quantification of total phenolic content (TPC) and total flavonoid content (TFC). Antioxidant activity were determined using DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP). Above all, fresh samples showed the significant highest value for all assay tested. However, among all blanching time, blanching at 2 min showed the significant highest values compared to other time parameter for all assay (TFC:136.17 ± 2.50µg QE/mg; TPC: 24.58 ± 0.07µg GAE/mg; DPPH: 52.00 ± 0.23%; FRAP:66.11 ± 0.24 µg TE/mg extract). However, there was no significant different between 2 min and 5 min blanching for the TPC assay tested. 15 min of blanching time reported about 70% loss of antioxidant activity using DPPH radical scavenging assay. Using Pearson correlation, TPC and TFC showed there were positive correlation between antioxidant content with antioxidant activity assayed by DPPH scavenging assay (r=0.975 and r=0.947, respectively) and FRAP assay ( r=0.967 and r=0.959, respectively). Time recommended for food processing which involve blanching was not more than 5 min to avoid major loss in the antioxidant potential. Future studies on shorter time interval is needed to verify the findings in present study.