Bound and free Ca concentrations varied with salt dip and
time of storage (Fig. 6). As in experiment 1, dipping in Ca salts
resulted in an immediate increase in bound Ca concentrations on
melon tissue, except when Ca carbonate was used (Fig. 6A). This
salt showed a low solubility in the water dip. Ca carbonate may
not have penetrated through the melon tissue, which has a high
water content (more than 90%). For control and Ca carbonate
treatments, similar free and bound Ca levels were measured. No
statistically significant differences were found in bound and free
Ca concentrations among Ca chloride, Ca propionate and lactate
treatments (Fig. 6A). Ca treatments increased free and bound
Ca concentrations by 40% and 50%, respectively, (average of
Ca chloride, Ca propionate and lactate treatments compared to
control), and were positively correlated to firmness (Table 2).
Saftner et al. (2003) also increased the bound Ca level in Honeydew
melon pieces by more than two-fold using 0.6% Ca Chloride
and 0.7% Ca propionate, although they did not use a hot dip.