Heat and moisture transfer in baking of potato slabs

Heat and mass transfer in a slab of potato potato during baking were explai ned using a multiphase porous media model that includes internal evaporatio n and capillary, diffusive, and pressure driven transport of water and vapo r, The model also includes the effect of the formation of a surface "skin" during baking. Model predictions were validated using experimental data. Mo st of the temperature drop in the material occurs in a relatively thin and dry surface region, while much of the interior stays at somewhat uniform te mperature. Moisture content inside the material stays uniform except near t he surface region where it drops to very low values. Evaporation occurs ove r a significant region, as opposed to at a sharp front. Baking time reduces significantly with thickness, however at a slower rate compared to conduct ion-only heating (no moisture transport). In addition, the surface temperat ure also reaches a higher value for a thinner material, which may help deve lop the often desired crusty surface. The skin layer can reduce the vapor l oss from the surface, and consequently, increase the surface temperature an d center temperature so that the baking time can be reduced. This process i s sensitive to the permeability of the skin layer. Decreasing initial moist ure content in the food and increasing air temperature and the heat transfe r coefficient reduces baking time. The comprehensive nature of the model ma kes it relatively easy to extend it to hybrid processes such as microwave b aking.