Drying of Mint Leaves: Influence of the Process Temperature on Dehydration Parameters, Quality Attributes, and Energy Consumption

In this work, to assess the temperature effect on dehydration parameters and physicochemical characteristics of mint leaves, the samples were dried at air temperatures of 40, 50 and 60°C and constant air flow rate of 1 m s-1. Energy consumption of the process was also studied. Fick’s second law was used to model mass transport in the leaves during the process. Moisture diffusivity and coefficient of mass transfer were determined to vary in the range of 5.09×10-9-1.73×10-8 m2 s-1 and 1.59×10-5- 5.71×10-5 kgwater m-2 s-1, respectively. Both of the mass transfer parameters were increased with increasing temperature. Higher temperatures caused more total color change and destruction of both chlorophyll and carotenoids. While the rehydration capacity of the dried leaves increased, the specific consumed energy of the process diminished with increasing drying air temperature.