Infrared drying of dill leaves: Drying characteristics, temperature distributions, performance analyses and colour changes

Thin-layer drying behaviour of dill leaves samples under three different infrared radiation power intensities was investigated. Diffusion Approach was found to be the best model that describes the drying behaviour of dill leaves. Effective diffusivity values were 6.97 × 10 −9 , 6.84 × 10 −9 and 8.96 × 10 −9 m 2 /s for power intensities of 1790, 1970 and 2070 W/m 2 , respectively. According to the first and second law efficiencies, the infrared drying system was more efficient at higher power intensities (p < 0.05). However, the total colour change was maximum at the highest power intensity. For the investigated infrared drying conditions, 1970 W/m 2 was recommended as the best-infrared power intensity applied for drying of dill leaves by taking into account both performance analyses and quality changes.