Effect of convective and microwave methods on drying characteristics, color, rehydration and microstructure properties of ginger
Abstract In this research, the effects of convective drying method (60, 70 and 80 °C) and microwave drying method (160 and 350 W) on the drying characteristics, color, rehydration and microstructure properties of ginger has been examined. For the purpose of choosing the most appropriate thin-layer drying models in terms of the drying applications, nine mathematical models have been applied on the experimental data. Pursuant to the assessment of the statistical tests, models of Diffusion Approach, Midilli et al. and Page that represent drying characteristics are found to be better than other models. Drying applications have affected the color values of all fresh ginger samples. Results indicated that browning degree increases as drying temperature and microwave power rise. The samples dried at 60 °C has the maximum rehydration ratio while the samples dried at 80 °C has the minimum rehydration ratio. Scanning electron microscopy visuals have ascertained that the deterioration of the ginger samples remarkably surged due to the rise in either drying temperature or microwave power. Applying the convective and microwave techniques as an alternative drying method for ginger samples is possible.