Morphology of Date Fruits Depending on the cultivars as well as the stage of maturity, date fruit shows the greatest extent of variation in its shape, size, and color. Apart from changes in physical characteristics, date fruit varies greatly in chemical composition during its various stages of maturity.
As the date fruit matures, it undergoes major morphological and chemical changes that subsequently determine the overall quality and acceptability of this fruit. A lot of information on the physicochemical changes occurring in date fruits during different stages of maturity is now available from all the major date fruit growing countries of the world (Al- Hooti et al., 1997f; Mohammed et al., 1983; Shabana et al., 1981; Sawaya et al., 1982; Salem and Hegazi, 1971).Date fruits may have round, oval, oblong, or cylindrical shapes depending on the cultivar.
Al-Hooti et al. (1997f) reported the physical measurements and colors of five major date fruit cultivars grown in the UAE. All the cultivars were green in color at the kimri stage but at the khalal stage, the color varied among the cultivars.
At the khalal stage, Shahla and Bushibal were red, Gash Gafaar and Lulu were yellow, whereas Gash Habash fruits were yellowscarlet (Figs 22.1a–g). At the last stage of maturity (i.e., tamer ), the fruits of all the cultivars turned dark brown and shriveled considerably.
The fruit weight, pulp–seed ratio, and physical measurements at the various stages of maturity of these five cultivars have been described in detail elsewhere (Sidhu and Al- Hooti, 2004). At the kimri stage, the Bushibal and Gash Gafaar fruits are cylindrical in shape, whereas the Lulu fruits are nearly round.
These shapes are more or less retained by all cultivars throughout the various stages of fruit development. The lengths of Bushibal, Gash Gafaar, Gash Habash, and Shahla are 26.5, 24.8, 23.7, and 27.7 mm, respectively, with the corresponding values for width being 15.4, 15.5, 17.7, and 18.6 mm. In contrast, the Lulu cultivar has a length and width of 19.3 and 18.6 mm, respectively, indicating its nearly round appearance.
Fruit weights are generally the highest at the khalal stage (6.1– 10.0 g) and decrease subsequently toward the tamer stage (4.9 g). The pulp percentage varies from 83% to 90%, and the seed percentage varies from 10% to 17% among these five cultivars. The physicochemical characteristics of 55 Saudi cultivars (Sawaya et al., 1986a) at khalal and tamer stages of maturity are quite similar to those of the UAE cultivars reported by Al-Hooti et al. (1997f).
Some of Saudi cultivars had a bigger fruit size (25.6– 26.8 g) at the khalal stage, but itwas reduced to 13.7– 14.1 g at the tamer stage. The fruit weights ranged from 5.8 to 26.8 g (with an average of 13.5 g) at the khalal stage and from 4.8 to 18.3 g (with an average of 9.8 g) at the tamer stage. The weight of seeds ranged from 0.7 to 1.8 g at khalal stage and 0.6–1.3 g at the tamer stage of maturity of these cultivars. The pulp percentage of these cultivars was reported to be in the range of 86–96% and was slightly higher than that reported by Al-Hooti et al. (1997f), although some of the smaller fruit cultivars studied by them had similar fruit size and pulp percentages. Sourial et al. (1986) evaluated four local cultivars, namely, Sofr-Eldomain, Kabooshy, Sergy, and Homr-Baker, in relation to their control cultivar, Hayany, grown in Egypt for their physicochemical characteristics.
The fruit lengths for these five cultivars ranged from 4.9 to 5.6cmand fruit weights ranged from 15.79 to 25.30 g, seed weights ranged from 1.87 to 2.38 g, and pulp percentage ranged from 88.15% to 90.70%. These values were quite comparable to those reported earlier in the literature (Sawaya, 1986). In another study, Nour et al. (1986) reported the physical characteristics of nine dry palm cultivars (i.e., Balady, Bartamuda, Degna, Garguda, Gondalia, Kolma, Malkabi, Sakkoti, and Shamia ) grown in Aswan, Egypt.
The fruit weights, fruit lengths, fruit widths, and seed weights ranged from 6.5 to 16.9 g, from 3.89 to 5.40 cm, from 1.75 to 3.32 cm, and from 1.0 to 1.63 g, respectively. The cultivar Malkabi had the highest fruit weight (16.9 g), Shamia was the longest (5.4 cm), and Bartmuda had the smallest seed (1.0 g only).