An undesirable consequence of cutting is softening; tissue stress
results in a loss of firmness, principally owing to enzymatic hydrolysis
of cell wall pectic substances and the action of pectinolytic enzymes,
the decrease in cellulose crystallinity and the thinning of cell walls.
Ascorbic acid has long been applied in combination with organic acids
and calcium salts, particularly calcium chloride, to prevent enzymatic
browning and maintain fruit firmness.
The firmness of the control did not significantly decrease over the
8 days of storage. Coating with chitosan effectively retarded or avoided
tissue softening in the samples. This is in agreementwithmany previous
research papers, which have reported that CaCl2 treatment firms apple
tissue by strengthening the cell wall and middle lamella.
The results (Fig. 3) showed that 0.2%AA+0.5%CaCl2 +1%chitosan
treated apples had the highest firmness, since calcium chloride, a known