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 cellwall
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 calcium
treated groups was significantly (P < 0.05) higher than untreated
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. This finding is consistent with previous reports