ABSTRACT

The drying kinetics of sliced and splitted turmeric rhizome (Curcuma longa) was conducted using oven dryer at different drying temperature of 50 °C, 60 °C, and 70 °C and at different thickness of 2mm, 4mm, and 6mm. Fick's second law was used to calculate the moisture diffusivity and it was observed from the result that moisture diffusivity increases with increase in sliced and splitted thickness. Four models were used to verify the characteristics of drying curves: (Henderson and pabis, Page, Logarithmic, Wang and Singh). The drying characteristics of sliced and splitted turmeric rhizome were satisfactorily described by logarithmic model. The drying rate of sliced and splitted turmeric samples decreases with decrease in moisture content. The activation energy "Ea" was determined using Arrhenius equation and the following results was obtained; for sliced turmeric rhizome, it was determine to be 932.10kJ/mol for 2mm, 1235kJ/mol for 4mm and l614kJ/mol for 6mm. for splitted turmeric rhizome, it was determined to be -1364kJ/mol for 2mm, 826.80kJ/mol[ for 4mm and l3887kJ/mol for 6mm.this results shows that the activation energy "Ea" increases with increase in thickness for both sliced and splitted samples. It was also observed that moisture ratio of sliced and splitted turmeric rhizome decrease continuously with increase in drying time. With increase in drying air temperature, the drying time decreases considerably.