Although the two-phase and the deconvolution methods do
not give exactly the same CI values for a given starch sample, the
pattern of CI evolution (increase with respect to native starch CI
value in the 2–6 h interval followed by reduction of CI values in
the 6–48 h interval) is very similar for both methods. The described
increase-decrease CI pattern may be attributed to the discussed
preferential action of -amylases over the amorphous zones of
starch. A faster enzymatic removal of the less ordered regions of
starch should result in an initial increase in the samples CI values,
as the ones shown in Fig. 5. By the way, all three methods
used for CI determination exhibit highest values at around 6 hours
of hydrolysis, which interestingly coincide with the time interval
for which a reduction of the hydrolysis rate was observed by both
quantitative methods used to follow hydrolysis kinetics (Fig. 1).
An increase in starch crystallinity upon amylolysis has previously
reported for other systems. In the contribution of Zhou, Hoover,
and Liu (2004) the X-ray patterns of the hydrolyzed residues of
wrinkled pea starch showed thatthe relative crystallinity increased
substantially on hydrolysis (from 17.8 to 33.4%). Authors attributed
these results to the extensivedegradationofthe amorphous regions
of the starch granule. Based on differential scanning calorimetric
results, You and Izydorczyk (2007) also concluded that the overall
crystalline order in zero amylose starch increased due to partial -
amylolysis. On the other hand, and based on the observation that
-amylolysis did not produce an increase in crystallinity, a number
of researchers have concluded that -amylases can simultaneously
solubilize both amorphous and crystalline regions of starch granules
(Co