Annual Progress Report on Malting Barley Research March, 2007

M w kDa
800
600
400
200
0
0.4
0 2 4 6 8 10 12
Reaction Time (min)
molecular weight
iodine binding
Figure 5. Change in the weight average molecular weight (Mw) and iodine binding of
beta-limit dextrin when incubated with purified malt alpha-amylase under conditions of
the ASBC manual method for alpha-amylase.
The second portion of the study focused on study of the reaction of beta-limit dextrin
with purified malt alpha- and beta-amylase. Malt alpha-amylase was purified from a
crude Sigma (Sigma-Aldrich, St Louis) enzyme preparation by heat shock and
ultrafiltration. The freeze-dried enzyme preparation was standardized to yield
approximately 30, 60, and 90 DU in the manual method. Beta-amylase was from
Megazyme (Ireland). In the first series of experiments the loss of iodine binding with
alpha-amylase was monitored both in the presence and absence of beta-amylase.
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
OD 650
81