Themicrographs of native starch (Figure 2A) and samples treated
with AA along with the control samples are shown in Figure 2.
The surface of the native starch granules are generally smooth
while for the samples treated with AA before heating some spots
can be observed on the surface of starch granules treated with AA
before heating (Figure 2B). These spots are more obvious on Atype
(larger) starch granules. It has been reported that addition of
chemicals can cause some spots on the surface of the starch granules
(Majzoobi and others 2009; Majzoobi and others 2011). The
presence of some proteins on the surface of starch granules called
“starch granule-associated proteins” has been documented which
are strongly bonded to the surface of the granules (Baldwin 2001;
Israkarn and others 2007). It is possible that AA could have some
effects on these proteins and hence change the smooth surface
of the granules. The micrographs of the heated samples revealed
that these samples were fully gelatinized because no granule was
observed in the micrographs (Figures 2C and 2D).