Effect of steam blanching and convection drying conditions on color, vitamin c, total phenolic content, flavonoid content and antioxidation activity in soursop (annona muricata l.) Leaf tea

Anotace: Blanching and drying techniques in food processing greatly affect the bioactive values. Research into this effect on soursop leaves raw material in the processing of tea which is a plant with anti-inflammatory, anti-cancer properties. Through a steam blanching process, 4 minutes were selected for compliance with TPC (208.43 ± 0.80 mgTE/g DM) and TFC (43.21 ± 0.71 mgQuercitin/mg DM). Along with the typical antioxidant activities such as TPC, TFC, the TAA, DPPH, ABTS content decreased sharply when heated by convection drying oven at 50-65°C. About 80% of the content is lost at the highest drying temperature. In addition, the Lab* color space of the fresh sample is dark brown transformed by heat, producing a characteristic yellowish hue when extracting custard leaf tea in hot water.