Fig. 2 shows the effects of extrusion variables on expansion ratio,
percentage of gelatinised starch and resistant satrch content of
pea starch noodles. Expansion ratio decreased with decreasing
moisture content (Fig. 2A and B). The extent of physicochemical
changes during extrusion affects product expansion. The expanded
matrix in the extrudate was provided by the pea starch component.
The expansion process could be described as nucleation in
the die, extrudate swelling immediately beyond the die, followed
by bubble growth and collapse (Kokini, Chang, & Lai, 1991). This
phenomenon is influenced by degree of starch gelatinisation