2004 Volume 5 Issue 3 Pages 143-151
By the use of MRI, we clearly showed that starchy food has a complicated water content profile during cooking, a profile which is hard to be described by Fickian diffusion equation. In the search for the missing factor which governs the behavior of water absorption characteristic of starch, we come to the conclusion as follows: (1) There exists some confusion in the discussions of the published papers in terms of the usage of the word“gelatinization”. (2) The gelatinization reaction of starch should be understood in terms of“terminal extent of gelatinization”. (3) The information on the terminal extent of gelatinization as a function of temperature and water content at heat-treatment is of most importance. (4) The factor which governs the water migration in starchy food is“ceiling water content”which is the potential maximum of water holding capacity that a starchy food has. Fickian diffusion equation is applicable on a system that is homogeneous in terms of ceiling water content. We proposed Water Demand Model which has a potential to be applicable on a system that is inhomogeneous in terms of ceiling water content.
