THESIS

1.3.2 β-amylolysis (%)
114
β-amylase attacks the next to last glycosidic linkage from the
non- reducing ends on branched chains and specifically releases maltose. However,
this enzymatic action is blocked by α-D-(1,6) branched linkages (Zeikus, 1989). As
shown in Figure 26, the debranched sample by 14 and 16 unit/g starch of pullulanase
hydrolysis
for 16 hr showed higher β-amylolysis (96.27 and 98.82 %) than did the 8
to 12 unit/g starch concentration (66.60 to 83.48 %). These results indicated that the
14 and 16 unit/g starch of pullulanase hydrolysis the rice starch was nearly completely
debranched with 16 unit/g starch.
Typically, the starch was completely debranched when it has
been attacks by β-amylase at least about 95 %, more particularly at least about 98%,
most particularly at least about 99 % debranched by weight (Nagamura el al. 2002).
Beta-amylolusis (%)
120
100
80
60
40
20
0
0 8
Figure 26 Effect of pullulanase enzyme concentration (0 to 16 unit/g starch) on
β-amylolysis (%) of 16 hr debranching of 15% HARS preheated
at 121°C for 30 min
10 12 14 16
Enzyme concentration (unit/g starch)