Effective moisture diffusivity of garlic cloves undergoing microwave-convective drying

Drying of garlic cloves was done using microwave-convective technique, using microwave power of 10-40 W, air temperature of 40-70 degreesC and at air velocity of 1-2 m/s. The effective moisture diffusivity varied from 1.29 to 31.68 x 10(-10) m(2)/s. A third order polynomial relationship was found to correlate the effective moisture diffusivity (D-eff) with moisture content. The D-eff increased for the same values of drying air temperatures and velocities as the applied microwave power was increased. However, D-eff decreased at all temperatures and applied microwave power with increase in air velocity. The activation energy in the microwave-convective drying ranged between 4.08 and 10.50 kJ/mol, which was much lower than the convectionally heating activation energy values for moisture diffusivities for most vegetables. (C) 2004 Elsevier Ltd. All rights reserved.