Water sorption in pre-heat-treated wheat flour dough
2006
Yahata, Y.(Tokyo Univ. of Marine Science and Technology (Japan)) | ; Fukuoka, M. | ; Sakiyama, T. | ; Watanabe, H.
When starchy food such as rice grains or noodle strands are boiled for a few minutes, the food body can be interpreted as becoming a multiphase system in terms of water-holding capacity because uneven starch gelatinization takes place in the food body and gelatinization seems to govern waterholding capacity. In order to describe water migration in such a multiphase system, Relative Water Content Model (Water Demand Model is proposed. For the practical use of this model, information on water-holding capacity is required. In an attempt to measure the effect of temperature and water content on water-holding capacity, pre-heat-treated wheat flour dough packed in a cylindrical frame was immersed in water at 25 deg C and the time course of water content was observed. Unexpectedly, water content in the sample continued to rise for seven days even though the water content in the sample monitored by NMR imaging showed a flat profile. Since the standard water content to be used in Relative Water Content Model is not necessarily the maximum water content (ceiling water content), we defined first stage water-holding capacity as the water content when the rise of water content changed its rate after NMR imaging profile became flat. The first stage water-holding capacity collected in this way was favorably used to simulate the change of water content profile in a wheat flour dough slab that was temperature-gradient heat-treated.
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