Effective moisture diffusivity, moisture sorption, thermo-physical properties and infrared drying kinetics of germinated paddy

Abstract

Temperature and relative humidity (RH) dependence of moisture sorption phenomena for agricultural products provide valuable information related to the thermodynamics of the system. So the equilibrium moisture contents (EMC), effective moisture diffusivity (Deff) and thermo-physical properties in terms of void fraction, specific heat capacity, and the apparent density of germinated non-waxy Suphanburi 1 paddy were evaluated. Five commonly cited EMC equations were fitted to the experimental data among temperatures of 40-60°C correlating with RH of 0-90%. The results showed that the modified GAB equation was the best function for describing experimental results while those evaluated thermo-physical properties depended on moisture content. To determine drying kinetics model, the simulated values using Midilli et al. (2002) model and Page’s model was the best fitting to exact drying kinetics values for infrared (IR) and hot air (HA) drying, respectively. Finally, the Deff value of paddy dried with IR and HA sources were also evaluated and the calculated Deff value of both HA and IR drying was in order of 10-9 m2/s.

Keywords

• GABA rice
• drying modeling
• effective diffusivity
• long-grain rice
• thermo-physical properties