Effect of Microwave, Infrared and Freeze Drying Methods on Drying Kinetics, Effective Moisture Diffusivity and Color Properties of Turmeric

Abstract

In the present research, effect of methods that use the microwave (90, 160 and 350 W), infrared (60, 70 and 80 °C),and freeze drying for turmeric samples on the drying kinetics, effective moisture diffusivity and color were analyzed.Also ten distinct thin layer models of drying were used to predict their kinetics. Depending on the evaluation of thestatistical tests, models of Midilli et al and Wang & Singh models were found the optimum ones for explaining dryingcharacteristics of turmeric. Among the used methods, the fastest and slowest drying time was 65 min with microwavedrying (350 W) and 600 min with freeze drying, respectively. The calculations demonstrate that the maximum effectivemoisture diffusivity value is obtained in microwave drying (350 W). Our study shows that although the freeze-dryingincreases the drying time, it showed closest color results against to fresh samples. In conclusion, microwave, infraredand freeze drying methods applied to turmeric should improve with the combined drying applications.