Date flesh: Chemical composition and characteristics of the dietary fibre

The date by-products of two date palm (Phoenix dactylifera L.) cultivars, Deglet-Nour and Allig, from the Degach region (Tunisia), were analysed for their main chemical composition. Studies were also conducted on the physicochemical properties (colour, water and oil-holding capacity and theological behaviour) of dietary fibre (DF) extracted from date flesh. The following values (on a dry matter basis: DM) were obtained for fleshes of Deglet-Nour and Allig cultivars, respectively: sucrose 52.7% and 13.9%, glucose 13.7% and 29.9%, fructose 12.6% and 29.0%, total dietary fibre 14.4% and 18.4%, protein 2.1% and 3%, ash 2.5% and 2.52%. Insoluble DF, the major fraction of total DF, constituted 9.19-11.7% DM for Deglet-Nour and Allig, respectively. The elaboration of DF concentrates from date fleshes was characterised by an extraction yield of 67%. The chemical composition of these DF concentrates showed high total DF contents (between 88% and 92.4% DM) and low protein and ash contents (8.98-9.12% and 2.0-2.1% DM, respectively). The DF concentrates showed a high water-holding capacity (similar to 15.5 g water/g sample) and oil-holding capacity (similar to 9.7 g oil/g sample),and pseudoplasticity behaviour of their suspensions. Thus, date DF concentrates may not only be an excellent source of DF but an ingredient for the food industry. (c) 2008 Elsevier Ltd. All rights reserved

Physicochemical Characteristics of Date Sap Lagmi from Deglet Nour Palm (Phoenix Dactylifera L.)

Physicochemical properties of sap from Deglet Nour date palm (Phoenix dactylifera L.) were studied. Composition analysis revealed (on a dry-weight basis) a high content of carbohydrates (94.98 g/100 g of dry matter basis) mainly sucrose, 2.72 g/100g (dry matter basis) of proteins and 2.29 g/100 g (dry matter basis) of ash. Date palm sap also contains 7.64 mg gallic acid equivalent/100 ml of total polyphenol. Thus, date palm sap showed antioxidant activity with a percentage inhibition of the DPPH radical value of 47.64%. Surface and foaming properties were also performed by drop volume and bubbling method, respectively. Equilibrium surface tension of fresh sap was 63.51 mN/m. Freeze-drying method preserved surface activity. Native sap showed better foam power (1.03) and foam stability (1150 s) than solutions prepared from lyophilised sap (5-30 g /100g of solution). Results demonstrated that this natural juice could be regarded as functional food due to its high nutritional value, antioxidant activity, surface activity, and foam power

Heating Effects On Some Quality Characteristics Of Date Seed Oil

Effects of heating on some quality characteristics of date seed oil from two cultivars (Deglet Nour and Allig) has been investigated using an accelerated test in a Rancimat system. Fatty acid, viscosity, absorptivity at 232 and 270 nm, colour and total melting enthalpy of Deglet Nour seed oil were less changed compared to that of Allig seed oil, because the former contained a higher amount of total phenolic compounds (526 lg/g against 215 lg/g) and a lower content of unsaturated fatty acids. Viscosity and absorptivity at 232 nm and at 270 nm increased rapidly after reaching the oxidation induction time. Differential scanning calorimetry melting profiles of date seed oils were also changed after heating in the Rancimat. Melting enthalpies seemed to be constant during the initial stages of Rancimat treatment and then reduced after the induction time was reached. The obtained data shows that date seed oils were resistant to thermal treatment during a long period ( 30–40 h). This may indicate that they could bear thermal treatments that could be applied in refining procedures or in culinary treatments such as frying and cooking conditions. We could also expect that they may have a good shelf life