The thickness and film forming characteristics of chitosan film
were also affected by molecular weight of chitosan and viscosity.From the cross-section SEM images (Fig. 1), the arrows indicate the
chitosan film on coated mango peel. Mango fruit coated with HMCTS
exhibited the thickest of the chitosan film coating on mango
peel (3.47 ± 0.50 mm) while MM-CTS coated mango resulted in
thinner chitosan film coating (1.29 ± 0.45 mm). LM-CTS showed
very thin chitosan film, and consequently, the thickness of film on
the coated fruit could not be measured.
The arrows in Fig. 2 indicate stomatal aperture on mango peel in
control and LM-CTS coated fruit. Both HM-CTS and MM-CTS film
coating thoroughly sealed and completely covered stomata on
mango peel. However, HM-CTS was tightly compacted while MMCTS
exhibited a thin, semi-transparent film. LM-CTS coated film
was highly porous and did not thoroughly seal mango peel
resulting in exposed stomatal aperture. Thus, the dissimilar filmforming
properties of chitosan which are influenced by molecular
weight significantly impact postharvest qualities and physicochemical
characteristics of ‘Nam Dok Mai’ mango fruit during
storage.