some quality attributes and biochemical properties of nine iranian date (phoenix dactylifera l.) cultivars at different stages of fruit development

the fruit of date palm (phoenix dactylifera l.) is an important horticultural product in the middle east and north africa. among more than 400 reported date palm cultivars in iran, around 20 cultivars are more important due to having better eating quality and trading values. in this study, the fruit of nine commercially important date cultivars including ‘barhee’, ‘breim’, ‘deiri’, ‘fersi’, ‘gantar’, ‘khadravi’, ‘sayer’, ‘shakar’ and ‘zahidi’ were evaluated for certain quality and biochemical properties during the last three stages of ripening (i.e., khalal, rutab and tamar). the results showed that the highest levels of total soluble solids (tss) and titratable acidity were recorded at tamar stage for all studied cultivars. maximum tss was recorded for ‘deiri’ (77 %) and ‘zahidi’ (75.3%) which are considered as dry dates. by a similar pattern, the mean amount of soluble proteins, flesh darkening and peroxidase activity (pox) increased to 5587 μg g-1, 0.76 a410 and 5220 ug-1 tissue, respectively. fruit at khalal stage showed an incredible amount of phenolic compounds and antioxidant capacity, but these parameters of nutritional value reduced to their lowest level in almost all studied cultivars at tamar stage. flesh darkening as an index of appearance quality increased greatly by turning rutab into tamar for almost all cultivars.