Cell wall modification during ripening of 'Keitt' and 'Tommy Atkins' mango fruit.
Mitcham E. J., McDonald R. E.
Author Affiliation: USDA-ARS, US Horticultural Research Laboratory, Orlando, FL 32803, USA.
Journal of the American Society for Horticultural Science 117 : 919-924
Abstract : Fruits of the 2 cultivars harvested at the immature green stage were allowed to ripen in storage at 20°C. Tommy Atkins fruits developed more red and yellow pigmentation in peel and mesocarp tissues than Keitt fruits. The outer mesocarp remained firmer for longer in Keitt than in Tommy Atkins fruits. The inner mesocarp was softer than the outer mesocarp at all stages of ripening in both cultivars. The neutral sugars in cell walls, particularly arabinosyl, rhamnosyl and galactosyl residues, decreased as fruits ripened in both cultivars. Keitt fruits had more loosely associated chelator-soluble pectin, had accumulated more soluble polyuronides and retained more total pectin at the soft ripe stage than Tommy Atkins fruits. Polygalacturonase activity was similar in both cultivars and increased during ripening. The amount and molecular weight of cell wall hemicellulose decreased during ripening in both cultivars. These data indicate that enzymatic and/or non-enzymatic processes, in addition to polygalacturonase activity, are involved in the extensive softening of mango fruits.