The effect of temperature (35, 50, and 60°C) on the rehydration behavior of microwave‐dried amaranth (Amaranthus dubius) leaves was investigated. Leaves were dried at 700 W power level before rehydrating in water. The higher the rehydration temperature, the higher the equilibrium moisture content of the leaves, although the effect was not statistically significant. The increase in rehydration ratio was significant only as temperature increased from 50 to 60°C. The process was adequately described by the Peleg sorption model, with the Peleg rate constant (K 1) and the Peleg capacity constant (K 2), both decreasing as rehydration temperature increased. While the color difference (ΔE) between fresh leaves and leaves rehydrated at 35°C was significantly higher than for the leaves rehydrated at 50 and 60°C, this difference was not visible. Cooking of leaves occurred beyond 120 min at the higher rehydration temperatures . Based on the results, rehydration of microwave‐dried leaves was successfully carried out at 35°C, however, rehydrated leaves were darker than the fresh leaves. Increasing the temperature to 50°C improved the rehydration capacity and the color of the leaves, however, cooking of leaves occurred by the second hour of the process.

The effect of microwave power level (200, 500, 700 and 1000W) on the drying behaviour of amaranth (Amaranthus dubius) leaves was investigated. Higher microwave power levels effected faster drying and there was an increase in drying rate constant (k) as microwave power level increased from 200 to 1000W and an increase in diffusivity (D eff ) values from 3.04 x 10 -10 to 2.82 x 10 -9 m 2 /s. Leaves dried at 1000W power level however showed noticeable scorching after 540s of drying. Drying at the lower microwave power levels occurred in the constant and falling rate period, while at the higher power levels drying occurred in the falling rate period after an initial warm-up phase. Amaranth leaves could be dried at 700W power from an initial moisture content of 6.00 g H 2 O/g DM (85.7% wb) to 0.08 g H 2 O/g DM (7.6% wb) in 11.5 min. Overall, of the twenty-two thin layer models applied to the MR data, the Alibas model gave the best fit in terms of both the root mean square error (RMSE) and the chi-square statistic ( 2 ).