Abstract:Harvested pear （Pyrus pyrifolia） fruits were dipped in calcium solution to investigate the effects of calcium chloride solution treatment on the content of pectin, the contents of different soluble calcium, the changes in activities ofpectinesterase （PME） and polygalacturonase （PG） and on the fruit firmness. The results showed that calcium solution treatment significantly increased total calcium content in fruits, improved fruit firmness and maintained permeability of cell membrane significantly. The content of NaCl soluble calcium was highest in treated fruits, followed by water-soluble calcium, calcium acerate and HCl-soluble calcium. An increasee in water-soluble calcium was observed on the 21 st day in treated fruits, while NaCl soluble calcium decreased. The contents of water-, NaCl- and HCl-soluble calcium increased significantly after calcium treatment except for acetic acid soluble calcium. Calcium treatment delayed degradation process of pectin and inhibited PG activity, but had no obviously inhibitory effect on PME activity. Effect of calcium treatment on fruit firmness was probably related with the inhibitory effect of PG activity.
