Extraction and Determination of Antioxidant Activity of Vietnamese Butterfly Pea (Clitoria ternatia L.)

The objective of this study was to determine the optimal value of factors affecting the antioxidant activity extraction of antioxidant activity of butterfly pea flowers. The investigated factors included extraction temperatures (30, 40, 50, 60, 70 and 80°C), extraction time (30, 60, 90, 120 and 150 minutes) and solid to solvent ratio (1:05, 1:10, 1:20, 1:40 and 1:50 g/mL). The efficiency of extraction was evaluated based on antioxidant activities which were measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and ferric reducing antioxidant power assay (FRAP). The results showed that when the extraction process was performed at temperatures of 60°C, the resulting extracts with highest DPPH antioxidant activity (575.10 μmolTE/L) and FRAP (1093.83 μmolTE/L) was obtained. Considering the effect of extraction time on antioxidant activities of butterfly pea, time range of 30–90 minutes led to highest DPPH values while extracts with highest FRAP power were collected after 120 minutes. Moreover, decreasing solid-to-solvent ratio resulted in the decline in antioxidant activities.