Effective moisture diffusivity of garlic cloves undergoing microwave-convective drying Original Research Article

Drying of garlic cloves was done using microwave-convective technique, using microwave power of 10–40 W, air temperature of 40–70 °C and at air velocity of 1–2 m/s. The effective moisture diffusivity varied from 1.29 to 31.68 × 10−10 m2/s. A third order polynomial relationship was found to correlate the effective moisture diffusivity (Deff) with moisture content. The Deff increased for the same values of drying air temperatures and velocities as the applied microwave power was increased. However, Deff 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.