الفهرس 
Abstract
Chemical composition of Doum fruit pulpOnly 14 pages are availabe for public view
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Abstract
Doum (Hyphaene thebaica) fruit and doum-fruit flour DF were studied in terms of chemical properties as well as technological processes to prepare ordinary, free gluten biscuit and cake, containing DF. Wheat flour or maize flour substituted with five levels of DF; 0, 5, 10, 15 and 20% to produce biscuit and cake.
The obtained results could be summarized as the following:-
1- Data showed that wheat flour had higher levels of protein and carbohydrate content (12.85 and 84.13%) than doum flour (2.99 and 70.13%) and maize (8.86 and 80.76%, respectively). While doum powder had higher levels of crude fat, crude fiber and ash content: 2.69, 15.22 and 8.97% than wheat flour 72% extraction: 1.57, 0.82, and 0.63%, respectively.
2- Doum fruit flour has higher phenol content (4539.97 mg GAE/100g D.W) than wheat flour (1518.49 mg GAE/100g D.W), and maize flour (2132.93 mg GAE/100g D.W). The highest value of flavonoids was noticed in doum flour comparing with maize flour and wheat flour with values (2143.62, 735.73, 711.69 mg catechin/100 g D.W), respectively.
3- Minerals content of doum fruit flour showed the highest content of Ca, Mg, Fe and Cu compared with wheat and maize flour, while maize flour had the highest content of P with value 340.76mg/100g.
4- There were difference between the 100% WF biscuit and those substituted with doum fruit flour at different levels. However, ash and fiber contents of fortified biscuit samples were increased with increasing the level of doum fruit flour, but the total carbohydrates were decreased.
5- Substitution of wheat flour with doum fruit flour caused a significant increase in phenolics content proportionally with increasing the substitution level in biscuit. The highest value was noticed at 20% (1722.05 mg GAE/100g D.W) compared with control (1117.76 mg GAE/100g) and the other biscuit samples. Same trend was observed in flavonoids of the produced biscuits.
6- Results showed that Ca content in control wheat flour biscuit sample was 33.64 mg/100g, this value increased with increment of DF addition 5, 10, 15and 20%, which were found to be 45.89, 58.14,70.40, and 82.64% mg/100g, respectively. The data also showed that the concentration of P in control sample was found to be 162.32 mg/100g which is considered lower than that found in biscuit samples with addition of DF 5, 10, 15 and 20% which were 162.74, 163.16, 163.59 and 164.01 mg/100g, respectively.
7- Data revealed that the replacement of wheat flour by DF improved some studied sensory characteristics of biscuit. Therefore, both 5% and 10% doum flour could be recommended to be produce as biscuit with good quality acceptable sensory quality attributes.
8- The moisture content in maize flour biscuit (control) was 16.92%, which was found to be higher than the other treated biscuits which were 15.59, 15.34, 15.13 and 14.88%, respectively. The protein content of processed biscuits with different concentrations of DF 5, 10, 15 and 20% were 6.04, 5.75, 5.45 and 5.16%, respectively. The crude fat content of control sample was 15.02%, this value is higher than that of other biscuit samples with 5, 10, 15 and 20% DF which were found to be 14.80, 14.76, 14.59 and 14.45%, respectively. The caloric value or energy in maize flour – doum flour biscuit was decreased as a result of DF substitution, it ranging from 439.37 to 452.68 in treated samples comparing with 457.62 kcal/100g for control sample.
9- Substitution of maize flour with doum fruit flour caused a significant increase in phenolics content proportionally with increasing the substitution level. The highest value was noticed at 20% (2120.11 mg GAE/ 100g) compared with the control (1638.71 mg GAE/ 100g) and the other biscuit samples. The same trend was observed in flavonoids of the produced biscuits.
10- Free gluten biscuit (maize flour) made with DF were analyzed for Ca, P, Mg, Fe and Cu content. The results showed that Ca content in control sample was 31.65 mg/100g, this concentration increased with increment of DF addition by 5, 10, 15 and 20%, which were found to be 44.29, 56.94, 69.59, 82.24 mg/100g, respectively. Data also showed that the concentration of P in control sample which was found to be 344.59 mg/100g which is considered lower than that found in the biscuit samples contained 5%, 10%, 15% and 20% which were 334.50, 324.35, 313.61, 303.28 mg/100g, respectively.
11- With the increase in the level of doum flour from maize flour in the biscuit formulation, the sensory score for color, surface character, crumb colour, taste, texture and mouth feel of free gluten biscuits decreased slightly.
12- The sensory evaluation of wheat flour cakes results showed that there were significant differences between doum flour substituted cake samples in shape and crust color. Also, there were significant differences in crust characteristics, odor between samples and the control sample. Meanwhile, it showed that there were no significant differences between substituted samples in the acceptability at 5% followed by 10% levels of substituted cake.
13- The protein content of maize flour cakes with different concentrations of DF was ranged from 20.33 to 21.65%, comparing with 22.10% for control which made from maize flour only. The crude fat content of control sample was 21.91%, this value was higher than other cake samples with 5, 10, 15 and 20% DF which were found to be 20.87, 19.86, 19.32 and 18.90 %, respectively. The energy or caloric value of free gluten cake (maize flour substituted with DF) was ranged from 447.27 to 774.02 Kcal/100g, which was lower than control cake with value 488.11 kcal/100 g. This decrease as a result of substitution with DF in free gluten cake which was better for health.
14- The gelatinization temperatures and enthalpies varied significantly between cake samples under study. The onset temp (To) was ranged from 31.92 to 45.80°C, while peak temp (Tp) ranging from 102.71 to 125.61°C. On the other hand, end temp (Te) was significantly different among the flour samples with higher degrees. Te was highest in control YMF cake (170.72°C) and the lowest in WF+DF 15% (130.47°C). The ΔHP content ranging from 4.08 to 5.80 J.g-1 for all the studied cake samples with small significant differences between them. The PHI (peak high index) was ranged from 4.98 to 8.65% for cake samples under study.