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Consumption of sugary food is a major cause of health problems, while food shortages also pose a serious threat to public health. Recycling low-quality dates in food production can provide both economic and health benefits for producers and consumers.
Date fruit chemical analyses were conducted on the Shamia, and Sakkoti date fruit samples at the Rheology lab., Food technology research institute, in March 2021, according to AOAC (2005, 2012, and 2019), and it was found that:
There are no significant differences in moisture content, lipids, ash, and acidity between the fresh fruits of the Shamia and Sakkoti date varieties. The moisture content of all samples was in the range of 4.11 to 4.83%.
Sakkoti date contained more protein, lower reducing sugars, and Total Soluble Solids (TSS) than the Shamia date variety.
Sakkoti date fruit contained higher content of minerals such as calcium, magnesium, sodium, potassium, Iron, Zinc, and Copper than those of the Shamia date variety. However, Shamia date fruits contain more phosphorus than did Sakkoti variety.
Shamia date powder in the biscuit formula had lower sodium content. Increased magnesium content, while the incorporation of Sakkoti powder remarkably increased the potassium making biscuits more health beneficial than did the control biscuit samples.
Essential elements such as ferrous, zinc, and copper were increased by increasing the replacement ratio, especially when powder of Shamia date fruit was used.
Physical and mechanical properties experiments were conducted at the Agricultural System Lab., Agricultural Engineering Dept., Ain-Shams University, Egypt in 2021. It was found that:
The average length of the Shamia and Sakkoti date was found to be between 34-33 mm, respectively. Sakkoti dates have a bigger fruit width(16-17mm) than the Shamia fruits (15-16mm).
Sakkoti date fruits showed a higher hardness value (21.57 N) than that of Shamia (18.97 N). Based on this information, the crushing and milling energy for modeling date powder will be higher for the Sakkoti variety than that required for Shamia.
The average calculated toughness for Sakkoti date fruits was found between 15-20 N.m while Shamia fruits ranged between 10-15 N.m
Biscuits dough rheological characteristics experiments were conducted at the rheology lab of the Food Technology Research Institute (FTRI), Giza, Egypt. It was found that:
The amount of water necessary for the dough of the control sample was 59 cmᵌ H₂o /100g flour and gradually decreased to the level of 42 cmᵌ H₂o /100g flour by increasing the amount of incorporated date flour in the dough. It could be referred to the high amount of reducing sugar (mainly fructose) in the incorporated date flour, which builds up a viscous mass upon dissolving and help in reaching the 500 BU, while the control sample needs much water to hydrate starch and protein molecules in the flour, where they are responsible for the viscous structure of the dough. The water absorption was reduced by increasing the amount of fructose in the added date flour.
The control sample of the Biscuits dough (control) required 2 minutes to get the maximum copresence, while the incorporation of date fruit powder strongly increased the required time in the range of 6.5 min to 9.5 min, probably because of the relatively high fiber content of the date flour and to its rougher particles which required longer mixing time to be completely mixed and integrated into the dough matrix.
The biscuit dough stability time of the date powder-free dough (control) was 2.5min. This time was increased to the level of 9.5 to 16 min because of partially replacing the formula sugar content with different ratios of Sakkoti and Shamia date fruit powder. The reason for this long stability time could not be referred to the difference in protein and gluten content but rather too high viscosity of the developed dough (high Fructose content of replaced mixes), which sticks longer time at the rotating axis of the mixer until the dough starts to weaken.
The result revealed a significant difference in softening degree between the tested samples. The dough of the control mix showed a softening level of 70 BU. The incorporation of Sakkoti powder did increase the softening degree to 80 BU, while the incorporation of Shamia date powder did reduce the degree of softening to the level of only 40 to 60 BU.
Results of the control biscuit dough showed a maximal deformation (extensibility) of 85mm, which required high force (580 BU), and high energy (55cm²) to deform the dough. Incorporation of date fruit powder in the formula of biscuit production did increase the extensibility (deformation length) to the level of 105 to 110 mm except for those with 30% of Shamia powder, reduced the required tensile force (elasticity) to the level of 280 to 540 BU and consequently reduced the tensile energy to the level of 30 to 60 cm². The most optimal blending ratio for formulating a biscuit mix is the use of 20% and 30% powder from Shamia date fruit.
The corresponding dough showed a lower degree of softness (60 and 40 BU), suitable extensibility for forming the dough (105 and 70 mm) as well as energy value between 60 and 30 cm².
The R.N ratio number expresses the ratio between elasticity, from a rheological standpoint, and the elastic modulus of the obtained dough, which decreased with date powder incorporation.
A lower spread ratio value is a sign of the bitter rising ability of biscuits during the packing process. The majority of the tested biscuit samples showed lower spread ratio values than that of the control sample.
Biscuit sensory evaluation had been implemented at Food and Agric. Industries Technology Center (FAITC) on July 7th, 2021, according to ISO (6658, 14299, 11036, 5492, and 3972. It was found that
The treated biscuit was slightly darker in color than the control samples. Changes in the total color index (∆E) exhibited a negative indication, and the treated samples showed less color than the control sample. The induced color darkness is not only a result of Maillard browning reactions but with less extent due to direct sugar caramelization and oxidation induced by the phenolic components of date powder integration in the biscuit formula.
The moisture remaining in the biscuit is in the form of bound water covering the hydroxyl, hydrogen, and carboxyl groups of the sugar, starch, protein, oxidation, ats, and fiber chains with a mono H₂o. molecules to prevent oxidation of these compounds and, hence, the water activity of the dry biscuit is enough to prevent microbial contamination but did not protect the product from browning reaction and fat oxidation, which are still active even under very low water activity (a_w) values
No changes in protein and starch contents have been observed.
Biscuit samples produced by replacing a part of the sugar with date fruit powders showed higher content of crude fiber and reducing sugars and lower content of non-reducing sugar compared with the control sample.
The incorporation of Shamia date powder in the biscuit formula had lower sodium content.
Increased magnesium content, while the incorporation of Sakkoti powder remarkably increased the potassium making biscuits more health beneficial than did the control biscuit samples.
Generally, from obtained results of the penetration test it was found that biscuits made from Sakkoti date powder and sugar have a harder texture than biscuits made from Shamia date powder and sugar. While biscuits stiffness increased with the increase of the date powder replacement ratio. Biscuits made from Shamia date powder and sugar mixture were stiffer than Sakkoti biscuits.
The biscuit samples with incorporated date powder showed lower roughness and higher mouth feel scores than those of the control samples. Biscuit samples with 30% substitution sugar with date powder recorded higher sensory scores and were closer to the control sample, compared with those of 20% and 50% substitution.
Biscuits made from sugar replaced by 30% of date powder, were recommended according to nutritive content and texture sensory test.
Date powder incorporation in biscuits improves the biscuits’ general appearance, taste, texture, and crust color compared with the control.