Firmness is one of the important parameters reflecting the
postharvest storage characteristic of fruits. It is related to tissue
softening. Loss of firmness caused by the loss of integrity of cell wall
structure leads to wilting and shrinking of fruits (Qi et al., 2011). As
shown in Fig. 1b, firmness of the initial samples was 3.19 N before
any treatments. After 1 day of coating processing, firmness of cal-
cium treated groups was significantly (P < 0.05) higher than un-
treated control group. With calcium salt treatment, the firmness of
fruit increased slightly in the first couple of days of storage; this
might be due to chelate effect of calcium ions on pectin and other
related macromolecules within fruit flesh, leading to increased
firmness.