The effect of bed condition (fix, semi fluid and fluid bed), input temperature (40, 55 and 70C) and infrared power (500, 1,000 and 1,500 W) on moisture diffusivity (Deff), activation energy (Ea) and specific consumption of energy (SCE) of pistachio nuts was investigated. The infrared radiation effect in fixed bed drying was further related to the other bed conditions. The maximum value of Deff (1.75 ¥ 10-9) has been calculated at fix bed, air temperature of 70C and infrared power of 1,500 W. Infrared power, only in fix bed condition caused increase in Deff of pistachio nuts.Minimum and maximum of Ea for pistachio nuts under infrared condition varied from 25.95 to 56.07 kJ/mol. The maximum value of SCE (8.21 ¥ 106 kJ/kg) was obtained at fluid bed (air velocity of 3.35 m/s), input temperature of 70C and infrared power of 1,500 W. Effect of infrared power in compare with the other input parameters was insignificant.
