attributable
to the formation of inter-molecular hydrogen bonds
between NH3
+ of the chitosan backbone and OH−
of the starch. The amino groups (NH2) of the chitosan
were protonated to NH3
+ in the lactic acid
solvent, whereas the ordered crystalline structures
of the starch molecules were destroyed with gelatinization,
resulting in the OH groups being exposed
to readily form hydrogen bonds with NH3
+ of the
chitosan