Some physico-chemical properties of date fruit varieties.

In this study, some physico-chemical properties of date fruits were determined. Moisture contents of date pulp ranged between 13.43% (Khalas) and 16.17% (Sugei). Fat content of date pulp was found from 0.32% (Sugei) to 0.38% (Sukary), crude oil of seeds ranged 4.35% (Sugei) to 4.51% (Khalas). Sucrose and reducing sugar contents of date pulp were 57.17% and 42.83 % for Sukary, 0.59 % and 99.41 % for Khalas and 1.13% and 98.86% for Sugei, respectively. „L‟ values ranged between 49.93 (Khalas) and 50.69 (Sukary), while „a‟ values varied between 12.12 (Sugei) and 12.61 (Khalas). The date pulp oil contain from 15.86% (Sugei) to 24.16% (Khalas) palmitic acid, from 5.99% (Sugei) to 9.3% (Khalas) stearic, 23.88% (Sukary) to 27.31% (Sugei) oleic acid, from 30.1% (Khalas) to 35.99% (Sugei) linoleic acid, and from 10.7% (Khalas) to 14.8% (Sugei) linolenic acid.


INTRODUCTION
The date (Phoenix dactylifera L.) has been an important crop in the desert region of Arabian countries (Mohammed et al., 1983;Mrabet et al., 2008;Al Jasser, 2009). It is an important member of the family Palmaceae, providing a food for people in the arid and semiarid regions of the world (Saafi et al., 2008). Sawaya et al., (1983) reported that the moisture, total nitrogen, fat, fiber, ash, tannins, vitamin C, β-carotene and ten nutritionally important minerals of the date were highest in the early stages of development and decreased during maturation. Date fruits have phenolic compounds possessing antioxidant activity (Mansouri et al., 2005). The aim of this study was to determine the antioxidant activity, total phenol, nutritional value, mineral contents, and fatty acid composition of ripe date fruits purchased from local markets.

MATERIAL AND METHODS
Processed date palm fruits of three varieties (Khalas, Sugei and Sukary) were purchased from local markets. About 100 g of the sample was taken, stoned and the average pulp and seed weights were determined. A portion of the seed mixture was ground by a hammer mill and the moisture content was determined. The date part was dried at about 50 o C, and kept at +4 o C until analyses.
The moisture content of pulp and pits were established separately by drying a sample (about 5 g) in a drying oven at 100 ±5 o C during 24 h. Crude fat, crude fiber, crude ash, colour values of samples were determined according to the Association of Official Analytical Chemists (AOAC, 2003). Energy value was measured by IKA C2000 calorimeter (Sundy, China). Protein content was determined by the Dumas Nitrogen Analyzer (DNA) (Velp NDA 701-Monza, Brianza-Italy). Protein was calculated using the general factor (6.25).
Working conditions of DNA were the following: O 2 flow rate: 400 ml/min; He flow rate: 195 ml/min; Combustion reactor 1030 o C; Reduction reactor: 650 o C; Pressure: 881.0 mbar Total phenolic contents of date fruits were estimated using Folin Ciocalteu (FC) reagent as described by Yoo et al. (2004) with some modifications.
Sugars were extracted from 1 g of broyat by a 100 ml water solution. Surnagent was filtered by 0.45 micron filter, and was analysed by HPLC, using a chromatograph of the type Agilent 1100 . The mobile phase was distilled water. The separation was carried out on a Bio-RAD HPLC Carbohydrate Analysis Column Aminex HPX-87C Carbohydrate Column (300 mm X 7,8 mm). The flow rate was 0.60 ml/min. Sugar quantifications were made by comparison to the standards glucose, fructose and sucrose (Merck).
Results were analysed for statistical significance by analysis of variance (Püskülcü and İkiz, 1989).
Date fruits undergo many physical and chemical changes during maturation. Some of these changes, such as the decrease in the concentration of tannins, ascorbic acid and β-carotene directly affect their antioxidant capacity (Alaith, 2008). Those differences according to our studies may be attributed to the variability of the studied cultivars and also to the variability of the climatic conditions, different regions, the differences in time of harvest, post-harvest treatments, and the use of fertilizers. Generally, date palm varieties are a potential source of valuable nutrients. The analyses of the date pulp from these common varieties suggested that it could be used in food industries as an important and inexpensive source of sugars, especiall reducing sugars, which have nutritional and technological values (Saafi et al., 2008).