Firmness, pectin components and cell wall hydrolases of mango fruit following low-temperature stress

Mango (Mangifera indica L. cv. Nam Dokmai) fruits chilled for 21 d at 4 degrees C were firmer than non-chilled fruits during subsequent ripening at 25 degrees C. The cell wall contents of chilled fruit contained less water-soluble pectin, more ammonium oxalate-soluble pectin and less alkali-soluble pectin than non-chilled fruits. The increase in ammonium oxaIate-soluble pectin was at the expense of the alkali-soluble pectin and correlated with high pectinesterase activity in the fruit from low-temperature storage. Polygalacturonase and P-galactosidase activities were inhibited in chilled fruits. The relationships between delay in loss of firmness, and differences between activity of cell wall enzymes and pectin content of chilled and non-chilled fruits are discussed.