The physicochemical composition changes during palm ripening were studied. The activities of invertase
and cell wall-modifying enzymes, namely pectin methylesterase (PME), b-galactosidase (b-Gal), endo-
1,4-b-D-glucanase (EGase), and cellulase were monitored during growth and ripening of Shahani, Piarom
and Deiry cultivars with different textures. Also, we estimated the concentrations of six organic acids by
HPLC. Reducing sugars, most of organic acid, pH and TSS increased up to the full-ripe stage of all date
types. On the contrary, moisture, macro and microelements and proteins decreased during the same period.
Despite a considerable rise in invertase activity (200 units) during ripening of Shahani, no significant
trend could be discerned in Deiry cultivar (8 units) at different stages. Our results also showed that cell
wall enzymes were increased in activity during ripening and these increases were coincident with fruit
softening. Furthermore, our results showed that the composition and the variation of the chemical compositions
mainly depended on the cultivar and maturity stage