Abstract
An attempt was made to prepare a series of food models so as to obtain fundamental information on the role of moisture affecting heat transfer in foodstuffs during a variety cooking. The newly prepared models could be characterized by the concentrated disperse systems consisting of the solid phase dispersed in the liquid suspending medium, i. e. an equivalent mixture of cocoa powder and wheat flour forms the solid phase, and the liquid suspending medium consists of an optional mixture of water and corn oil. Thus, it was possible to control the total moisture of the models in a range from a minimum of 7.1% (0% in the liquid phase) to a maximum of 48.7% (100% in the liquid phase)without fracturing the original moulded shape during heat treatments. Young's modulus of the models increased from 7.09 × 104 Pa to 4.44 × 105 Pa at room temperature, while the moisture decreased within the range described above. The dependence of effective thermal diffusivity of the models upon moisture was estimated from the measurements of effective thermal conductivity, heat capacity and density. We could obtain a range of mean values from 6.3 × 10-8m2·s-1 at a minimum moisture (7.1%) to 9.6 × 10-8m2·s-1 at a maximum one (48.7%) for the effective thermal diffusivity of the models. A series of food models provided in this study will be expected to play a role in studying the effect of moisture on the heat transfer of foodstuffs during cooking.
