THESIS

151
to 59.99%, 2.79 to 55.96 and 2.78 to 53.04%, respectively. While, the raw RS III from
high amylose rice starch had a lowest starch hydrolysis rate from 0 to 180 min
between
1.53 to 43.61%.
The equilibrium concentration (C∞) of the hydrolyzed starch in
butter cake was significantly different (P≤0.05) by RS III replaced for wheat flour.
However, the 20% RS III-cakes greatest lower C∞ value than the wheat flour-butter
cake. The kinetic parameters that describe the hydrolytic process of starch digestion
were obtained (Table 27). The wheat flour-butter cake and the 5 and 10% RS IIIsubstituted
butter cake gave slightly lower kinetic constants than white bread sample
but not significant difference (P≥0.05). The 15 and 20% RS III-substituted flour in
butter cake had significantly (P≤0.05) lower k value then the control butter cake.
While, the RS III from high amylose rice starch had lowest in k value (0.022). This
suggests that the addition of RS III had altered the intrinsic susceptibility of the starch
component in butter cake to digestion. Therefore, it confirmed that differences in the
digestibility of the RS III-butter cake were
due to a fraction of enzyme resistant starch
type III from high amylose rice starch.
Thus, hydrolysis rate was markedly slow for RS III-butter cake
and faster for the control butter cake. The low and slow hydrolysis rate of starch in the
20% RS III-butter cake is noteworthy, since the digestion experiment was performed
at equivalent of digested starch content in the butter cakes. Analysis data from starch
hydrolysis rate was used to calculated area under curves, hydrolysis index and
estimated glycemic index in the developed butter cake samples in the following
section.