The bioactivity of chitosan is a function of its physicochemical
properties which have an effect on film forming characteristics. Different physicochemical
properties of chitosan solutions which were classified as high (HM-CTS), medium (MM-CTS), and low (LM-CTS) molecular weight
chitosan are shown in Table 1. The respective SEM images are
shown in Fig. 1.
It was found that more than 98% of chitosan materials of three
different molecular weights could dissolve in 0.5% acetic acid
(Table 1). All chitosan materials showed percentages of moisture
content between 10 and 12% suggested that the
viscosity of chitosan solutions is affected by the molecular weight
of chitosan, the concentration of solution, the ionic strength, the
pH, and the temperature. HM-CTS showed the highest viscosity,
and LM-CTS showed the lowest viscosity which related to the
molecular weight of the chitosan samples. In addition, the samples
presented a degree of deacetylation (DD) between 84 and 91%
which had no significant differences. Therefore, the expected differences
in response of coated mango fruit should be mainly due to
the molecular weight of the chitosan applied.