The aim of this work was to study the mass transfer kinetics during fluidised-bed drying-toasting of soaked soybean to provide design information for production of whole soybean snack. The experimental work consisted of determinations of thin layer drying-toasting curves of soaked soybeans in a fluidised-bed dryer at air temperatures between 100 and 160 degrees C, for 60 min, using an air velocity of 2.5 m/s. The analytical solution for short times was not suitable for this high temperature process. In contrast, calculations by complete analytical solution for constant diffusion coefficient (D-eff) and constant radius (R-0), an infinite convergent series, were markedly accurate. However, previous studies on particle density and volume revealed non-negligible shrinkage during drying-toasting, possibly caused by the fact that the ratio of D-eff. to R-2 remains substantially unaltered. Values of the diffusion coefficient (around 10(-9) m(2)/s) and activation energy (31 kJ/mol) are within the ranges expected for food drying at elevated temperatures. (C) 2013 Elsevier Ltd. All rights reserved.