Weibull distribution for modeling air drying of coroba slices

Application of Weibuil distribution model was investigated for describing the moisture content of coroba slices during air drying. One set of experiments was performed following a full factorial design at three levels for air temperature (71, 82 and 93 degrees C) and velocity (0.82, 1.00 and 1.18 m/s). The set was designed to assess the adequacy of the Weibull model to describe water losses. The high regression coefficients (R-2 > 0.99) and low reduced chi-square indicated the acceptability of Weibull model for predicting moisture content. Values of scale parameter ranged from 41.77 to 71.52 (min) and values of shape parameter ranged from 1.06 to 1.21. Temperature sensitivity of scale parameter increased with increasing air velocity from 0.82 m/s (E-a = 210.45 J/mol) to 1.00 m/s (E-a = 214.93 J/mol) and then decreased with increasing velocity to 1.18 m/s (E-a = 139.03 J/mol). The normalized Weibull model was investigated for determining the effective diffusion coefficient (D-e). The D-e values ranged approximately from 2.51 x 10(-12) m(2)/s to 4.27 x 10(-12) m(2)/s. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.