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 deg rees C were firmer than non-chilled fruits during subsequent ripening at 25 degrees C. The cell wall contents of chilled fruit contained less water-so luble pectin, more ammonium oxalate-soluble pectin and less alkali-soluble pectin than non-chilled fruits. The increase in ammonium oxaIate-soluble pe ctin was at the expense of the alkali-soluble pectin and correlated with hi gh pectinesterase activity in the fruit from low-temperature storage. Polyg alacturonase and P-galactosidase activities were inhibited in chilled fruit s. The relationships between delay in loss of firmness, and differences bet ween activity of cell wall enzymes and pectin content of chilled and non-ch illed fruits are discussed.