Drying of gelatinized whole wheat

Whole grains of gelatinized durum and soft wheat were dried by forced and n atural convection at 40, 60, 80, and 100 degreesC. Magnetic resonance image s taken periodically during drying indicated that Fick's diffusion is not a pplicable to describe the moisture transfer during drying of the gelatinize d wheat grains. A simple mathematical model based on overall moisture balan ce fitted the experimental data very well. The drying took place in the fal ling rate period, which was approximated by two regions - first and second falling rate periods (FFRP and SFRP). The internal drying coefficient linea rly increased with increasing drying temperature, and was almost an order o f magnitude (from 10(4) to 10(5) s(-1)) higher during FFRP than SFRP. The s oft wheat dried faster than the durum wheat. The effect of forced convectio n was more pronounced during FFRP than SFRP.