Effect of the drying methods on total phenolics, total flavonoids and antioxidant activities in Ya-Nang leaf (Tiliacora triandra) powder

Abstract

The objective of this research was to study the effect of different drying methods on the amount of total phenolics, flavonoids and antioxidant activity in the Ya-Nang leaf powder using 2 drying methods, were 1) sun drying 2) hot air drying (50 °C 6 h, 60 °C 5 h, 70 °C 4 h) used distilled water as a solvent, then extracted under temperature 80 °C for 45 min. The extract was analyzed for total phenolics content, total flavonoids content and antioxidant capacity measured using DPPH free radical scavenging activity, ABTS free radical scavenging activity, total antioxidant capacity and reducing power. The results found that the drying process at hot air 60 °C for 5 h shown the best condition of total phenolics content (11.277 ± 0.158 mg GAE g–1 powder), total flavonoids content (9.485 ± 0.362 mg CE g–1 powder), DPPH free radical scavenging activity (23.293 ± 0.352 mg AAE g–1 powder), ABTS free radical scavenging activity (10.155 ± 0.393 mg AAE g–1 powder), total antioxidant capacity (32.382 ± 0.414 mg AAE g–1 powder) and reducing power (16.037 ± 0.039 mg AAE g–1 powder). The results indicated the appropriate drying method at 60 °C for 5 h made the Ya-Nang leaf powder contains high bioactive compounds and antioxidant activities. It can use for further development of commercial Ya-Nang tea products. GRAPHICAL ABSTRACT HIGHLIGHTS Preparation of Ya-Nang leaf (Tiliacora triandra) powder by hot air and sun drying Extraction by distilled water Analysis of active component and antioxidant activities