and starch breakdown Only the starch granules that have
been gelatinised could participate in the formation of a stable
expanded structure whereas excessive molecular degradation
resulted in poor expansion . Starch gelatinisation
and breakdown depend on mechanical and thermal energy
inputs. The results from our study showed that extrudates
from low moisture content expanded less than from high moisture
content. This may be due to their high viscosity at low moisture
content inside the extruder resulting in high shear rates that cause
a predominant molecular disruption of amylopectin molecules,
which seems to inhibit an increase in expansion (Fletcher,
Richmond, & Smith, 1985).