Modeling the moisture transfer during baking of white cake

Moisture transfer characteristics of cake batter during baking in a convective oven were investigated. The moisture content profiles of a thin layer of cake batter were experimentally determined, through baking at the oven temperatures of 50, 80, 100, 140 and 160 °C. The experimental oven temperatures were selected in order to cover the possible batter temperatures attained by the cake during a complete baking process. The data were analyzed analytically to calculate the effective moisture diffusivity. The analytical solution used the method of slope of drying curves, and the moisture diffusivity was related to the temperature and the average moisture content of cake batter. The temperature dependency of the moisture diffusivity followed an Arrhenius type equation. The moisture diffusivity increased with decreasing moisture content exponentially at 100, 140, and 160 °C, whereas it could be well constant at 50 and 80 °C oven temperatures. This was attributed to the difference in structure of product during baking at different temperatures. The overall non-linear regression of the results defined the effective moisture diffusivity as a function of both average moisture content and temperature of cake batter. For validating the predicted moisture diffusivity values and equations, the baking process was simulated by a numerical method using implicit finite difference technique. The drying curves from numerical solution, which used the predicted moisture diffusivities as input variables, were compared to the experimental drying curves and a very good agreement was achieved.