THESIS

Degree of starch hydrolysis (%)
90
80
70
60
50
40
30
20
10
0
0 30 60 90 120 180
Hydrolysis time (min)
RS III-0%
RS III-5%
Figure 33 Average hydrolysis curves of butter cake prepared with
RS III
replacement for wheat flour in butter cake product.
b) Hydrolysis index and glycemic index
RS III-10%
RS III-15%
RS III-20%
Raw RS III
White bread
153
Starch hydrolysis index (HI) of each butter cake was obtained by
using an Area Under Curve (AUC) in the starch hydrolysis rate from 0 to 180 min of
the butter cake samples divided by AUC of white bread. The glycemic index (GI)
value of each sample was obtained by using the starch hydrolysis index in the formula
by Goni et al. (1997). The butter cake with the added RS III had a significantly lower
HI compared to the wheat flour cake. A HI of 62.95% was determined in wheat flour
cake, which significantly different (P≤ 0.05) from that of 5, 10, 15 and 20 % RS III
replaced wheat flour-cake (Table 29). The hydrolysis index of 5, 10, 15 and 20 % RS
III replaced wheat flour-cakes were 55.72%, 47.90%, 44.74% and 43.57%,
respectively. These results showing that glucose liberation from RS III added butter