Abstract:

The effects of water temperature and water to flour ratio on moisture distribution and transfer characteristics in
hot-water dough were studied using low-field nuclear magnetic resonance (LF-NMR), and the ultrastructure of the dough
was observed under scanning electron microscope (SEM). The results showed that the bound and free water contents in hotwater
dough decreased and the adsorbed water content increased with an increase in water to flour ratio. Increasing water
temperature resulted in an initial increase followed by a decrease in the bound water content but the opposite changes in the
adsorbed and free water contents in hot-water dough. The ultrastructure was affected greatly by water temperature, and the
surface of the dough became more uniform and smooth as a result of starch gelatinization. The starch particles were tightly
stuck with gluten structure and their voids consequently became smaller with an increase in water to flour ratio.

Key words: hot-water dough, low-field nuclear magnetic resonance, scanning electron microscopy, moisture migration;ultrastructure