Modeling the moisture diffusivity in a baking cake

Full factorial baking (drying) test was performed with five levels of initial moisture contents (0.369, 0.431, 0.539, 0.611 and 0.707 d.b.) of cake batter and four levels of oven temperatures (40. 70. 100 and 200 degreesC) in duplicate. The moisture diffusivity (D-e) was then evaluated through the first falling rate period from plotting the dimensionless moisture ratio against time on a semi-log scale. For this moving boundary problem, simple volume compensation method was applied to the analytical solution. The moisture diffusivity was 9.0 x 10(-11) to 4.4 x 10(-8) m(2)/s for the industrial cake batter during baking. As porosity (epsilon) and temperature (T) of the batter increased the moisture diffusivity increased. The semi-empirical model developed was D-e = 29.6epsilon exp(-8020.5/T). Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved.