Biology Reference
In-Depth Information
suggested that enzymatic resistance of complexes increases with increasing
amylose degree of polymerization, lipid chain length, and complexation
temperature. They further reported that enzymatic hydrolysis of these
complexes give rise to two or more dextrin subpopulations, which origi-
nates from a sequence of lamellar units with interconnecting, amorphous
amylose chains. Fats high in saturated, monounsaturated, or polysaturated
fatty acids have been reported to lower the GI of breads with no signifi-
cant difference between the type of fat
(
Henry, Lightowler, Newens, &
Pata, 2008
)
.
The more common types of
-amylases are of protein or glycoprotein
Dreher, & Berry, 1984
). A wide variety of food crops such as beans, rye,
wheat, and oats contain amylase inhibitors in varying quantities. Non-
proteinaceous amylase inhibitors such as polyphenolic compounds or phe-
nolic acids, acarbose, isocarbose, acarviosine-glucose have also been
reported (
Farias et al., 2007
). Some oligosaccharides derived from microbes
also produce inhibitors which may inhibit the amylase activity. Amylostatin
and acarbose are two of the alpha amylase inhibitors produced by a fungi
Streptomyces
and bacteria from family
Actinoplanaceae
, respectively. Many
molecules that exist in plant sources are capable of inhibiting the activity
of
a
a
-amylase. Results from clinical studies have shown that the natural
inhibitors isolated from white beans significantly reduce the peak of post-
prandial glucose in healthy and type 2 diabetic subjects (
Boivin, Flourie,
-Amylase inhibitors of wheat do not affect
the wheat amylase activity but are known to inhibit mammalian salivary and
pancreatic
a
-amylase (
Lankisch, Layer, Rizza, & DiMagno, 1998
)
. Some
low molecular weight plant-derived molecules, such as luteolin, strawberry
extracts, and green tea polyphenols, have also been observed to inhibit
a
a
-Amylase inhibitors from kidney beans have the highest inhibitor activ-
ity though it is pH dependent. Some of these inhibitors have a greater affinity
for salivary amylases than pancreatic amylases. The amylase inhibitors pre-
sent in legume crops are generally inactivated at or above 100
C. Amylase
inhibitors tend to be specific against particular amylases. The inhibitor forms
a complex with amylase and causes reduction in starch digestion. Many
inhibit the activity of exogenous
-amylases such as those produced by
insects and may play a role in protecting the seed against predation. Others
affect endogenous
a
a
-amylases and as such may participate in regulating
