Studies on starch include examination of water absorption, chemical
modifi cation of molecules, behavior under agitation, and
high-temperature thermomechanical abrasion resistance.
Although starch is a polymer, its strength under stress appears
to be low. At temperature above 150°C, the glycoside bonds
start cracking and over 250°C starch granules subside endothermally.
At low temperatures, however, some reorganization
of hydrogen bonds is observed together with straightening of
the molecule chains during the cooling process (retrogradation).