MODELING WATER ABSORPTION OF SORGHUM DURING SOAKING

Water absorption of sorghum during soaking in water at temperatures of 10, 20, 30, 40 and 50 oC was simulated using Peleg's model. The weight gain during soaking process was determined in terms of moisture content. Peleg's equation was adequately capable to predict water uptake of sor- ghum under the experimental conditions. The Peleg rate constant, k 1, and capacity constant, k 2, de- creased from 11.8◊10 -2 to 0.95◊10 -2 h % -1 and 2.46◊10 -2 to 2.06◊10 -2 %, respectively, with increas- ing temperature. The effective diffusivity was eval u- ated by fitting experimental absorption data to Fick's second law of diffusion. Effective diffusivi ty of water varied from 8.376◊10 -12 to 2.22◊10 -12 m 2 .s -1 over the temperature range studied, with an energy activation of 24.21 kJ.mol -1 . The temperature de- pendence of the diffusivity coefficient was describ ed satisfactorily by Arrhenius-type relationship.