Effect of drying methods on antioxidant capacity, total phenolic and flavonoid contents of Phakwan (Sauropus androgynus (L.) Merr.) powder

Abstract

Effect of three different drying methods on antioxidant capacity, total phenolic and flavonoid contents of Phakwan (Sauropus androgynus (L.) Merr.) powder were investigated. Samples were dried with three difference methods (sun drying, oven drying and sun-oven-drying), then ground and extracted with methanol as crude extract. DPPH free radical scavenging activity, total antioxidant capacity and reducing power were used as markers for antioxidant capacity. TPC were measured using the Folin-Ciocalteau assay. TFC were assessed using based on the formation of a complex flavonoidaluminium. The oven-dried samples had TPC (23.37  0.70 mg GAE g–1 dry extract), total antioxidant capacity (120.10 ± 9.23 mg AE g–1 dry extract and 229.05 ± 8.55 mg BHTE g–1 dry extract) and reducing power higher than that of the sun-dried and sun-oven-dried samples while the sun-oven-dried samples had TFC and DPPH free radical scavenging activity higher than that of oven-dried and sun-dried samples. There was no significant difference in efficiency between sun and sun-oven-drying methods. The variation of antioxidant capacity, TPC and TFC of Phakwan (Sauropus androgynus (L.) Merr.) powder are due to the effect of the three difference drying methods.