Drying and quality characteristics of flos lonicerae in modified atmosphere with heat pump system

Abstract

Modified atmosphere drying of Flos Lonicerae is conducted, and the effects of drying temperature and oxygen content on drying characteristics and product quality are investigated in this study. Nitrogen gas is aerated into the dryer to adjust the oxygen content, and a heat pump system is used to control the drying temperature. The results showed that the increase in drying temperature and the decrease in oxygen content could improve the drying rate and effective moisture diffusivity. Increase in chlorogenic acid and chlorophyll contents as well as decrease in color difference were observed with decreasing drying temperature and oxygen content. High product quality could be achieved at all drying temperature levels when oxygen content was as low as 5%. Therefore, reducing oxygen content in the drying atmosphere is an effective method to improve product quality. © 2013 Wiley Periodicals, Inc.