Hydration characteristics of paddy in the parboiling process

Abstract

Hydration of 'Bombuwala' and 'No 341' paddy varieties in hot water was studied as a function of time and temperature. The temperature range from 45° C to 70° C and time of soaking not exceeding 4 hours were considered. Becker's diffusion equation was used to predict the soaking behavior of paddy. The activation energies of the diffusion through the grain were calculated using Arrhenius-type equation for diffusion. Results show that to achieve a 30% (d.b.) hydration of paddy at 70°C paddy should be soaked in water for 4 hours. Bomuwala paddy variety showed a higher hydration ability compared to No. 341 paddy variety.