الفهرس 
Gum arabic (GA) treesOnly 14 pages are availabe for public view
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Abstract
Gum Arabic (GA) or Acacia gum is an edible biopolymer obtained as
exudates of mature trees of Acacia senegal and Acacia seyal which grow
principally in the African region of Sahe in Sudan. The exudate is a nonviscous
liquid, rich in soluble fibers, and its emanation from the stems and
branches usually occurs under stress conditions such as drought, poor soil
fertility, and injury. There are close to 900 acacia species capable of
producing gum. Structurally, GA is a neutral or slightly acidic salt of a
complex polysaccharide composed of galactose, arabinose, rhamnose,
glucuronic acid, 4-O-methylglucuronic acid, calcium, magnesium, and
potassium. The molecular weight has been reported to be 600,000. Gum
arabic is distinguished from other gums by its high solubility in water; 50%
solutions can be prepared, compared with maximum concentrations of 5% or
less for most other gums.
The use of GA dates back to the year 2000 BC when the Egyptians
used it as an called ”Gum arabic” because was exported from Arabian ports.
Today, the properties and features of GA have been widely explored and
developed and it is being used in a wide range of industrial sectors such as
textiles, ceramics, lithography, cosmetics, pharmaceuticals and food. On the
other side, the effective biological role of GA has confirmed in the last
twenty years including reduction in plasma cholesterol level in animals and
humans, anticarcinogenic effect and antioxidant effect; with a protective role
against hepatic and cardiac toxicities. In addition to that, it has been claimed
that GA alleviates effects of chronic renal failure in humans. Also, GA is indigestible to both humans and animals, not degraded in the intestine, but
fermented in the colon to give short-chain fatty acids, leading to a large
range of possible health benefits. One of these benefits is its prebiotic effect
reported that four week supplementation with Gum Arabic (10 g/day) led to
significant increases in Bifidobacteria, Lactobacteria, and Bacteriodes
indicating a prebiotic effect. Several epidemiological studies suggest that a
high intake of dietary fiber, including GA (dietary fiber > 80%), is
associated with beneficial effects on fat metabolism. It can serve to reduce
obesity and therefore prevent associated complications in humans including
coronary heart disease, stroke and diabetes.
Therefore, the present study will carry out in a trial to open up new
horizons for the use of GA in some food processing applications through
fortify the wheat flour with GA in order to enhance its rheological properties
subsequently improve the resulted bread. Also, the addition of GA to beef
meatballs, one of the most important meat products, in a trial to add some
biological roles to the product will be in the scope of this investigation.
The data of the present study could be summarized as follow:
I. Properties of gum arabic (Acacia senegal)
− Data shows the contents of moisture, total protein, crude fat, crude
fiber, ash and carbohydrates content of GA collected from Sudan
Republic were 12.01, 2.34, 0.13, 82.56, 2.19 and 0.77%, respectively.
− Results indicated that gum arabic (Acacia senegal) had specific
rotation (-28.90) and relative viscosity (15.85). The Refractive index
(1.34), pH (4.36) and average molecular mass (384 kDa)− The extractive value for GA in different organic solvents was very
low (0.030-1.735%) while very high in water (15.00-16.25 %).
II. Food industry applications
The effect of GA on the Rheological properties of wheat flour
Farinograph measurements
− The results reveal that the control dough sample (without the addition
of GA) has a sginificant higher absorption (57.2) than the samples of
dough with the additions of GA (55.2).
− Dough development time (mixing time, min), statistically significant
difference was found between the control sample and the doughs with
additions of GA (3 g.100g-1). The increasing dough development time
illustrates that the dough with the addition of GA a longer relaxation
time (the dough is tougher).
− Dough stability in minutes is the most important index for dough
strength. Addition of GA to flour samples showed markedly longer
stability periods than the control samples (without the addition of
GA).
− Regarding FQN, an improvement in the quality of the doughs
occurred after the addition of GA, when the FQN value significantly
increased in comparison with the control sample.
Extensograph measurements
− The control dough sample (without the addition of GA) has a
significant lower extensibility (174) than the samples of dough with
the additions of GA (194). − Dough resistance to extension in B.U. is the most important index for
dough ability to retain gas. Addition of GA to flour samples showed
markedly increasing resistance to extension (548) than the control
samples (without the addition of GA, 510).
III. The effect of GA addition on the biological role, chemical,
microbiological and organoleptic properties of beef meatballs
Antioxidant activity of beef meatballs with different natural extracts
added and mixed with GA
− The addition of different plant extracts (GWE, garlic water extract;
RWE, Rosemary water extract and CWE, cinnamon) showed
considerable increasing in antioxidant activity and recorded AA
ranged 41.61- 77.21% in contrast 27.59% for control sample
(meatballs without addition the plant parts) when it was calculated by
the four different methods used in this study.
− The addition of GA with the plant parts extracts to the meatball
samples induced more increasing in AA and recroded values ranged
34.26 – 83.22% when compared with the simillar samples without GA
addition. RWE samples showed strong activity followed by CWE and
GWE, respectively.
− Mixture of used plant extracts with GA recorded the lowest
decreasing followed by MB+RWE+GA; MB+Mixture;
MB+CWE+GA; MB+RWE; MB+CWE; MB+GWE+GA; MB+GA;
MB+GWE and MB, respectively. The values of almost plant extracts
with GA absorbances throught 120 min are coming well i.e. over the line of 50 mg .L-1 of BHT and very close to 50 mg.L-1 of α-tocopherol
and 200 mg.L-1 of BHT . By the same manner, the tested plant
extracts without GA are coming over the line of 50 mg.L-1 of BHT.
These data proved the high stability of the all tested plant extract and
GA when comparing with that more comman standards BHT and α-
tocopherol.
Rancidity evolution of beef meatballs with different natural
extracts added and mixed with GA, during storage time
− The analysis of variance for the TBA data indicates that the TBA
values were significantly affected (P < 0.05) by both the extract
treatments and the storage period. Initial TBA values for all extract
samples were significantly lower than those for the control (P < 0.05).
Also, the addition of GA with the plant parts extracts to the meatball
samples induced more decreasing in TBA when compared with the
simillar samples without GA addition.
Bacteriological examination of beef meatballs with different
natural extracts added and mixed with GA, during storage
time.
− The analysis of variance for the LAB data indicates that the LAB
levels were significantly affected (P < 0.05) by both the extract
treatments and the storage period. Initial TBA values for all extract
samples were significantly lower than those for the control (P < 0.05).
Also, the addition of GA with the plant parts extracts to the meatballSensory evolution of beef meatballs with different natural
extracts added and mixed with GA, during storage time.
− The analysis of variance for the sensory scores indicates that the
sensory scores were affected by both the extract treatments and the
storage period. Initial sensory scores for all extract samples were
significantly higher than those for the control (P < 0.05). Also, the
addition of GA with the plant parts extracts to the meatball samples
induced more increasing in sensory scores when compared with the
simillar samples without GA addition.