"The objective of this research was to improve the solubility of chitosan by Maillard
reaction with 1% chitosan and 2% reducing sugar (glucose or glucosamine) dissolved in 0.2 M acetic
acid, which was adjusted to pH 6.0, and incubated at either 50°C or 70°C for 1–7 days. The physicochemical and rheological properties of the chitosan–saccharide derivatives were also investigated.
Results indicated that the solubility of modiﬁed chitosan derivatives was signiﬁcantly greater than that
of native chitosan. The solubility of chitosan–glucosamine was higher than that of chitosan–glucose,
and the chitosan–glucosamine derivative remained soluble at pH 10. The degree of deacetylation of
the derivatives decreased with increasing reaction time. Rheological investigation revealed that the
apparent viscosity of the water-soluble chitosan derivatives in aqueous solution depended upon system conditions such as pH, ionic strength, and solution temperature. The measured apparent viscosity
decreased as all system conditions increased. As calculated by the Arrhenius equation, the activation
energy (Ea) of the derivatives in aqueous solution generally decreased with increasing the extent of
Maillard reaction with respect to the reducing sugars used."