University of Khartoum

Effect of Cultivar and Location on Quality Attributes of some Sudanese Dates (Phoenix dactylifera L.) Fruits and the Traditional Method of Extraction and Syrups Quality

Effect of Cultivar and Location on Quality Attributes of some Sudanese Dates (Phoenix dactylifera L.) Fruits and the Traditional Method of Extraction and Syrups Quality

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Title: Effect of Cultivar and Location on Quality Attributes of some Sudanese Dates (Phoenix dactylifera L.) Fruits and the Traditional Method of Extraction and Syrups Quality
Author: Idris, Sit Ellail Hussein Abd Elkarim
Abstract: This study aimed to assess the effects of cultivar and location on the physical quality (fruit length, width, weight, seed and pulp weights and pit%) and on the contents of chemical components (protein, fat, fiber, ash, carbohydrate, Mg, Ca, Na, K, Fe, Zn, Cu, Mn, Co, Pb, Ni, total and reducing sugars, sucrose, fructose, glucose, pectin, poly-phenols) of three common date cultivars, Barakawi, Gondella and Tamoda. One sample of each cultivar was collected from two locations, Marawi and Karma (in the northern state) during October. The study was carried out for the seasons 2010 and 2011 and every season was assessed separately. The data were analyzed using SAS system. Atomic Absorption Spectrophotometer and Flame Photometer were used to determine macro- and micro- minerals. HPLC (High performance liquid chromatography) was used to determine sucrose, fructose and glucose contents. For the two seasons studied cultivar showed significant (P≤0.05) effect on fruit and pulp weights and pit%. Barakawi had the lowest fruit weights (6.08 and 7.15gm) and pulp weights (5.12 and 6.14gm) and largest pit% (16.22 and 14.13%). Barakawi and Tamoda had similar fruit length and width but Tamoda had smallest pit%. In the two seasons, Marawi cultivars gave significantly (P≤0.05) larger fruit length and width except for Gondella of season 2011 which had similar fruit length and width for the two locations. In the two seasons Barakawi had higher ash content (2.72 and 2.59%). Carbohydrate content of the cultivars of season 2010 ranged within 85.66 - 87.22% and of season 2011 within 80.32-82.26%. The three cultivars studied contained Mg, Ca, Na, K, Fe, Zn, Cu and Mn. Presence of Pb and Co was evident but did not depended on cultivar, location or season. Fe content of the cultivars ranged from 7.27 - 10.25 mg/100gm. Marawi cultivars showed higher (P≤0.05) levels of Mg, Na, Mn and Cu. Total and reducing sugars of the cultivars of the two seasons ranged from 61.63-75.23% and 50.41-75.35%. Marawi cultivars showed higher levels of reducing sugars and fructose contents. Sucrose was not detected in water extracts of dates and sugars were available mostly as fructose and glucose in equal amounts. In 70% ethanol extracts, sugars were available as sucrose, fructose and glucose in equal amounts. In the two seasons Barakawi had the lowest pectin content and Tamoda gave the highest pectin content. The general trend indicates that contents of chemical components of the cultivars depended on season. The study also aimed to assess the traditional method used to produce date extracts. Intact fruits were soaked in water then boiled in covered aluminum pan using gas cooker to extract the dates. Extract was separated by sliding the cover and filtered using fine screen. Gondella and Tamoda needed more time of boiling. For 15 min boiling, Gondella and Tamoda produced extracts with total soluble solid (TSS) 20% and 16.5% compared to 24.5% for Barakawi. For 22 min boiling, Barakawi, Gondella and Tamoda produced extracts with 31.5, 32.5 and 27% TSS respectively. It was not possible to use 3: 1 water to fruit ratio for Gondella and Tamoda due to foam formation. According to results Barakawi and Gondella were selected to produce syrup. Syrup was produced by concentration under vacuum at 58°C. During concentration the Gondella extract showed foaming and produced syrup which was accompanied with foams. Foams formed a separate upper layer (1:1) with time. Extract and syrup produced from Barakawi and Gondella were assessed.TSS of Barakawi and Gondella extracts were 31.5 and 28%,pH 5.58 and 5.35, acidity 1.08 and 1.92%, color reddish yellow for both, fructose 13.23 and 13.81%, glucose 12.40 and 12.76%. TSS of Barakawi and Gondella syrups were 76 % and 65%, pH 5.49 and 5.47, acidity 2.95 and 1.99%, color reddish yellow for both, fructose 32.30 and 28.06%, glucose 31.69 and 26.28%, sucrose was not detected in extracts and syrups. Results confirmed that use of intact fruits simplifies separation and filtration of the water extracts of the dates studied and that Barakawi was the best cultivar to produce water extract by this method and to produce syrup. The higher extractability from Barakawi was due to smaller thickness of the pulp, lower pectin content and comparatively higher fiber content. The maximum quantity of soluble solids extractable from one kilogram of intact Barakawi in a single extraction was 214 gm and maximum total sugar recovered was 207 gm. Gondella and Tamoda had higher pulp weights. The three cultivars were rich in the essential minerals (Mg, Ca, Na, K, Fe, Zn, Mn and Cu). Sugars were mainly in form of fructose and glucose. Marawi cultivars had larger fruits, higher in some minerals, reducing sugar and fructose content.
URI: http://khartoumspace.uofk.edu/123456789/27048


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