2006 Volume 57 Issue 4 Pages 229-237
The disturbance of thermal conduction in foodstuffs during heating in a metal vessel due to phase transition of the food components could be controlled by adding a variety of thermo-insensitive ingredients such as pure cocoa powder, ground green tea, powdered charcoal, and the ash from rice husk. Experiments confirmed that the pronouncedly disturbed curve of increasing internal temperature of a plastic fat system consisting of a mixture of tristearin and corn oil could be transformed into a smooth curve without affecting the endothermic heat of melting of tristearin in the presence of adequate amount of each thermo-insensitive ingredient. It was also confirmed that the disturbance of thermal conduction caused by the sol transition of a series of hydro-gels of agar or gelatin disappeared in the presence of certain amount of each thermo-insensitive ingredient. The resulting smooth curve of increasing internal temperature for a plastic fat or aqueous hydro-gels could be applied to an exponential equation characterized by the retardation time, while the heat capacity and thermal diffusivity of all the samples to be tested decreased with increasing amount of each thermo-insensitive ingredient introduced.
