Abstract:
Through a four-step top-down approach, native tapioca starch (NTS) was thermally acid-hydrolyzed, periodate-
oxidized with subsequent removal of iodine species (i.e., IO
4
(), IO
3
(), I(), and I
), and dialdehyde tapioca
starch (DTS) alcohol-precipitation. The percent yield was ~91%. Analyses confirmed the presence of aldehydic
functionalities (~71%), effectual iodine species removal (~98%), and enhanced water-solubility (~96.57%).
Besides, the combined treatment significantly reduced the M
w
2
(~57.81 kDa) and ameliorated homogeneity as
well as thermal stability (T
max
~ 667.15
C). Structural-spectral characterization also confirmed the presence of
aldehydic functionality, polymorphic transition (C- to A-type), and a higher degree of crystallinity (~91.77%),
the latter further corroborated by thermal analysis. The morphological study revealed that the combined
treatment reduced size (~393.55-nm-diameter and ~5.22μm-length)
and
changed
shape
into
rod-like
crystals.
DTS
showed
considerably
and
significantly
low
cytotoxicity
to
HaCaT
cells
in
vitro
at
the
concentrations
assayed
over
the
test
period
(24
h).
DTS's
conformation
was
most
stable
at
289
kcal/mol
and
151.7
au
heat
formation
and
minimum
potential
energies,
respectively.
Overall,
these
results
demonstrated
that
the
combined
treatment
had
no
deleterious
effects
on
NTS's
properties,
thus
yielded
DTS
with
ideal
properties
for
multifarious
uses.
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