Traditional drying methods involve high temperatures that degrade heat-sensitive compounds.
Dehumidified-air drying, an alternative to traditional drying methods, is suitable for heatsensitive
compounds; however, it consumes a large amount of energy and is comparatively
expensive. In this study, a multi-chamber dehumidified-air dryer was designed to dry Hydrocotyle
bonariensis, and the retention of the polyphenol content of Hydrocotyle bonariensis under
various drying conditions was examined. Multi-chamber dehumidified-air drying involves two
chambers; each chamber was operated at temperatures of 30, 40, and 50o
C with air volumetric
flow rates of 30 and 50 L/min. The results indicated that the highest retention of total phenolic
content and total flavonoid content, 24.67 mg of GAE/g dry weight (DW) and 2.204 mg of
catechin/g DW, respectively, was obtained at 50o
C with a 50 L/min air flow rate in the first
drying chamber. Multi-stage dehumidified-air dryers have the potential to dry heat-sensitive
products with reduced energy consumption.