A large variability in susceptibility to amylases
shown by raw starch granules also influences RS formation.
Potato starch and high amylose maize starch are known to be
very resistant in vitro and incompletely absorbed in vivo, whereas
most cereal starches are slowly but virtually completely digested
and absorbed in vivo (Holm and others 1987). The smaller surface-
to-volume ratio of the large potato granules is probably important.
The nature of the granule surface also needs to be considered;
an adsorbed layer of non-starch material would effectively
impede the action of the enzyme (Ring and others 1988). Raw
tepary starch is found to be more resistant to hydrolysis than
maize starch, perhaps due to differences in granule structure and
amylose content