Compositional characterization of endosperm (guar gum) from Six guar
(Cyamopsis tetragonoloba) Genotypes Grown in Sudan * Murwan K.
Sabahelkheir H. Abdelwahab Abdallah ** and * Department of
Biochemistry, School of Biotechnology, Faculty of Science and
Technology, Al Neelain University, Sudan ** Department of Agronomy,
Faculty of Agriculture, University of Khartoum, Sudan. Abstract: This
study was conducted in 1999, University of Khartoum. Six guar genotypes
were grown in the Sudan from 45 genotypes selected for the study. The
results showed that of the chemical composition of the endosperm of
guar seed as follows: 4 8-8. 7% moisture, 3 5-5. 0% protein, 0 5-0. 9%
ether extract, 0 5-0. 8% ash, 1 4-2. 0% crude fiber and 83 3-87. 5%
carbohydrates during physical signs are: 1 2337 refractive index, 0
20-0. 47 relative viscousty (distilled water as a solvent), 0 37 -. 56
relative viscousty (4% NaCl as a solvent), 5 0-7. 0 pH value, from 20
to 76 specific rotation, and 0 -. 035 0. 050 optical density. Ash
compositions of endosperm are: 13 000-19. 000 ppm potassium, 55
000-100. 000 ppm sodium, 2 500-13. 000% magnesium, 15 000-22. 000%
phosphorus and 11 000-38. 000 ppm of iron. The total available
carbohydrates such as mannose and galactose were ranged 67-73% and
28-33%, respectively. Ratio of mannose to galactose was 2:1 in the
endosperm. Keywords: Guar, endosperm, mannose and galactose. 1. 0
Introduction guar seed (Cyamopsis tetragonoloba) of the trunk (30
-33%), endosperm (27 -30%) and Keim (43 -47%) together. The germ and
hull of the guar as guar flour, rich in protein, will be used for
animal feed known. The seed has toxic effects, but lately advanced
research was carried out on the seeds to reduce its toxic effect and
the proper animal nutrition as a rich source of protein (Murwan, 1999).
The endosperm is commercially important role in guar seeds, since it is
converted into powder rubber. It contains 41% of dry matter and acetone
insoluble solids from the seed, 3 to 11% of the nitrogen and
phosphorus. At least 75% of acetone insoluble solids of the endosperm
are galactomannose and 12% being accounted for as pentosans, protein,
pectin, phytin, ash, and dilute acid insoluble residue (John, 1976).
The Guar is a crop gained economic importance after the discovery of
rubber-like substance (galactomannan) in its endosperm (Murwan, 2008)
galactomannans are together from 1 to 4 mannan backbone with varying
degrees on a 1 to 6 of galactose substitution and found in the cell
walls of legume endosperm (Marten et al., 2001). Guar seeds are a rich
source of mucilage or gum which forms a viscous gel in cold water and
an emulsifier, thickener, stabilizer in a wide range of food and
industrial application uses (Marina et al, 2007). Guar galactomannan
has a mannose to galactose (M: G) ratio of 6:1 (Edwards et al, 1992).
Pure mannan without galactose is completely insoluble in water and the
increasing substitution of galactose to increase the solubility of the
polymer, by attending (Noble, 1986 and Stephen, have become) 1983. The
mannose to galactose ratio of 2:1, guar gum is insoluble in organic
solvents, molecular weight range is 50 000-80. 000 and rubber is a
white to yellowish white, nearly odorless, free flowing powder with a
mild flavor (Yoko, 2008). Objectives of this study were estimated to
have grown the next analysis, physical properties of minerals content,
mannose, galactose, mannose, galactose, and ratio of tannin content of
endosperm of guar sex genotypes in Sudan. 2. 0 Material and Methodology
2 1 collection and processing of samples: Sex guar genotypes (X1H6,
X1H7, X2H0, X2H4, X2H6 and X2H8) were collected by the Department of
Agronomy, Faculty of Agriculture, and the University of Khartoum,
Sudan. The seeds of the guar sex genotypes were soaked in water for 12
hours and then slapped his hand to separate the endosperm from the hull
and germ. The separated endosperm were then dried at 105oC and then
ground to go to 0. 2 mm sieve. 2. 2 Chemical analysis: protein,
moisture, ether extract, ash and crude fiber content was determined
described by AOAC (1984). Carbohydrate content was calculated by
difference. 2. 3 Physical Analysis: refractive indices, determined the
specific rotation, relative viscousty, pH value was ad-optical density,
described by AOAC (1990). 2. 4 Ash composition: mineral content of
endosperm were extracted by the method of Pearson (described 1970). The
measurement of minerals was done using atomic absorption. 2. 5 Total
available carbohydrates: total available carbohydrate content of the
endosperm have been identified and described in the
anthrone method of
Clegg (1958). Galactose and mannose dilution: 100 mg of galactose were
dissolved in 100 ml of distilled water (1 mg = 10 ml). Then 10 ml of a
strong galactose solution was dissolved in 100 ml of distilled water to
dilute the solution of galactose. The same procedure was done to dilute
the mannose
anthrone reagent (0. 1%): 100 mg
anthrone in 100 ml of
sulfuric acid solution (270 ml concentrated H2SO4 was dissolved in 300
ml distilled water). Procedure: One ml of each diluted sample,
galactose and mannose in a series of test tubes 1, 2 a.m. to 3 p.m.,
respectively pepetted. Then 5 ml of anthrone reagent was added each
test tube, then contents of each test tube was heated in a water bath
for 12 minutes and allow to cool to room temperature. Spectrophotometer
at 360 nm was set up so that the scale zero map with distilled water.
Then read the diluted sample, galactose and mannose were. CHO-galactose
(mannose)% = 25 XBSXA Where: B = Reading diluted sample, A = Reading
dilute galactose (mannose) and S = weight of sample 2 sources. 6
tannin: Quantitative determination of tannin was for each separate
endosperm described using the modified vanillin-HCl in methanol method
by Price et al (performed 1978). A standard curve was prepared to
express the results as catechin equivalent, ie amount of catechin is
(mg / ml), corresponding to a color intensity that given by tannins
after correcting for blank. 2. 7 Statistical Analysis: A test of
homogeneity of error variance for each variable was done according to
Gomez and Gomez (1984). 3. 0Results and discussion 3rd 1 Chemical
composition: Table 1 shows the composition of the next six genotypes
endosperm of guar seeds. The moisture content of the endosperm ranged
from 4th 8-8. 7% which is higher than that of Thomas (1980) and given
less than reported by Stein, Hall and Co. (1962). The results showed
that highly significant difference in moisture content at the level of
(p? 0. 05). Protein content was 3rd 5 to 5 0%. The results are given in
agreement with the results of Thomas (1980). These results showed there
are significant differences in protein at the level of (p? 0. 05).
Ether extract of endosperm ranged from 0 5 to 0 9% reported in the area
of Mary (1988). The findings indicated that significant differences at
the level of (p? 0. 05). The ash content ranged from 0 5 to 0 8%,
within the range reported by Stein, Hall and Co. (1962), falls. The
results showed a significant difference exists at the level of (p? 0.
05). Crude fiber content ranged from 1 4-2. 0%, which is online with
this area of the stone, Hall and Co. (1962). Moreover, there is no
significant difference in the level of (p? 0. 05). Carbohydrate content
was of 83 can be varied. 3-87. 5%, is higher than the values of Thomas
(1980) reported. The results showed a significant difference exists at
the level of (p? 0. 05). 3. 2 Physical signs: Table 2 illustrates the
physical properties of guar seed endosperm of six genotypes. The
average values of the refractive index are: 1 2337. The results showed
that there were no differences in refractive indices of concentration 0
1 mg / 100 ml for the entire endosperm. Relative viscousty the
endosperm ranged from 0 20 to 0 47 (water as a solvent) and used
different from 0. 37 to 0 65 (used 4% NaCl) as solvent. It was found
that the relative viscousty is used in 4% NaCl as a solvent, is higher
than that used distilled water as a solvent. These findings indicated
that the relative viscosity revealed by the types of solvents, the
results indicate that there are important differences in distilled
water and 4% NaCl at the level of (p? 0 for. 05). pH values vary from
5th 0 – 7 0, the report within reach of Whistler (1954), fell. The
findings indicated that significant differences at the level of (p? 0.
05). Specific rotation ranged from + 20 to + 76. In addition, there are
significant differences at the level (p? 0. 05). Optical density ranges
from 0 035-0. 050. The results showed that significant differences at
the level of (p? 0. 05). 3. 3 Ash composition: Table 3 illustrates the
composition of the ashes of six genotypes endosperm of guar seeds. The
average range of 13 potassium. 000-19. 000 ppm. The findings indicated
that there was no difference in the level significantly (p? 0. 05).
Sodium content varies of 55 000-100. 000 ppm. The results showed that
highly significant difference in the level of (p? 0. 05). Calcium from
3 were mean. 500-5. 500 ppm, gave the results that there were
significant differences at the level (p? 0. 05). Magnesium content
varies from 2 500-13. 000%. She pointed out that highly significant
difference in the level of (p? 0. 05). The average values of phosphorus
ranged from 15 500-22. 000%. The results showed that highly significant
difference in the level of (p? 0. 05). Iron content varies from 11
000-38. 000 ppm. It turned out that it is highly significant difference
in the level of (p? 0. 05). 3. 4 Total available carbohydrates and
tannin content: Table 4 illustrates the total available carbohydrates
and tannin content of endosperm of guar genotypes sex semen. Total
available carbohydrates such as mannose ranged from 67 to 73%, while
the total available carbohydrates such as galactose ranging from 28 to
33%. These results showed that the mannose to galactose ratio is 2: 1,
these values up to Whistler (1954), Painter (1979) and (Yoko, given in
2008) is similar, but it is distinguished from (Edwards et al value
1992). The tanning was mg/100g 445 to 450. The results were similar for
guar seeds soaked in water for different time intervals have been
reported (Majed et al. 2006). Moreover, there is no significant
difference in the level of (p? 0. 05). Conclusion: It is noted that the
different chemical, physical, ash composition, total available
carbohydrate and tannin content is controlled by genetic or
environmental factors, among which plant material were tested
Confirmation: Authors very grateful to the soul of Dr. Karmalla KA
Department of Food Science and Technology, Faculty of Agriculture,
University of Khartoum, Sudan, to which we express our thanks for his
enormous patience continuous advice, careful and fundamental freedoms
throughout the study. Reference: 1 AOAC (1984). Official Methods of
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DC 21st . Yoko K. (2008). Guar gum, Chemical and Technical Assessment
(CTA), 2008 – Page 1 (4). Ph. D. 69TH JECFA. Table 1: Proximate
analysis of an endosperm (guar gum), guar genotypes of sex. Parameters
/ Samples Moisture% Protein% Ash% ether extract%% crude fiber
carbohydrates X1H6 6%. 5 3. 5 0. 5 0. 5 1. 5 87. 5 X1H7 7th 4 4. 5 0. 9
0. 5 1. 4 85. 3 X2H0 4th 8 4. 4 0. 8 0. 8 1. 9 87. 3 X2H4 8th 7 4. 0 0.
7 1. 3 2. 0 83. 3 X2H6 7th 8 5. 0 0. 7 0. 8 1. 9 83. 8 X2H8 6th 8 5. 5
0. 7 1. 0 1. 4 84. 6 Each value * is obtained from two average
repetitions in the dry. Table 2: Physical signs of the endosperm (guar
gum), guar genotypes of sex Parameters / Samples refractive index
Relative viscousty pH Specific rotation optical density (water) (4%
NaCl) X1H6 1st 2337 0. 47 0. 48 5. 0 + 36 0. 035 X1H7 1st 2337 0. 29 0.
65 5. 0 + 76 0. 035 X2H0 1st 2337 0. 33 0. 45 5. 0 + 59 0. 035 X2H4 1st
2337 0. 25 0. 37 7. 0 + 75 0. 050 X2H6 1st 2337 0. 47 0. 64 6. 0 + 17
0. 040 X2H8 1st 2337 0. 20 0. 45 5. 0 + 20 0. 040 * Each value is the
average obtained from two repetitions of the dry matter. Table 3:
Mineral contents (K, Na, Ca, Mg, P and Fe), endosperm (guar gum), guar
genotypes of sex Parameters / Samples K Na Mg Ca ppm ppm ppm Fe% P%
X1H6 16 pages / min 000 65 . 000 5. 500 7. 500 15. 500 11. 000 X1H7
19th 000 100. 000 3. 500 7. 500 22. 000 26. 000 X2H0 19th 000 65. 000
3. 500 2. 500 19. 000 11. 000 X2H4 13th 000 85. 000 3. 500 4. 000 18.
000 37. 000 X2H6 16th 000 75. 000 4. 500 13. 000 17. 000 38. 000 X2H6
18th 000 55. 000 3. 500 2. 500 19. 000 15. 000 * Each value is the
average obtained from two repetitions of the dry matter. Table 4:
mannose, galactose and mannose to galactose ratio of the endosperm
(guar gum), guar genotypes on sex samples X1H6 X1H7 X2H0 X2H4 X2H6 X2H6
mannose (M)% 70 71 67 73 70 71 galactose (G)% 30 33 33 28 30 29 M: G
ratio 2:1 2:1 2:1 2:1 2:1 2:1 tannin mg/100 g 445 450 450 445 430 450 *
Each value is the average obtained from two repetitions of the dry
matter.
