ISCA Journal of Biological Sciences _____ ______________________________ ______ __ _ _ ISCA J. Biological Sci. Vol. 1 ( 1 ), 67 - 7 0 , May (201 2 ) International Science Congress Association 67 Short Communication Quality Assessment of Guar Gum (Endosperm) of Guar ( Cyamopsis tetragonoloba ) Sabahelkheir Murwan K. 1 , Abdalla Abdelwahab H. 2 and Nouri Sulafa H. 1 1 Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, Al Neelain University, SUDAN 2 Department of Agronomy, Faculty of Agriculture, University of Khartoum, SUDAN Available online at: www.isca.in (Received 29 th March 201 2 , revised 5 th April 201 2 , accepted 13 th April 201 2 ) Abstract This experiment was conducted in l Lab. of Department of Biochemistry and Food Science Faculty of Agriculture, University of Khartoum, Sudan. Six guar genotypes were used for this study The results revealed chemical compositions of endosperm of the guar seed are as : 4.8 - 8.7 % m oisture, 3.5 - 5.5 % p rotein, 0.5 - 0.9 % f at, 0.5 - 1.3 % a sh, 1.4 - 2.0 .% f iber and 83.3 - 87.5 % c arbohydrates. While physical characters are:1.2337 r efractive indices, 0.20 - 0.47 r elative viscosity (H 2 O as solvent), 0.37 - .56 r elative viscosity (4% NaCl as solvent), 5.0 - 7.0 pH, 0 .035 - .0.050 o ptical density and +28 to +76 s pecific rotation a sh compositions of endosperm are p otassium: 57 – 79 mg/Kg, s odium 242 – 755 mg/Kg, c alcium 11 – 24 mg/Kg, i ron 49 – 287 mg/Kg, m agnesium 0.2 – 0.09% and p hosphorus 15 - 22 % . The total avail able carbohydrates as mannose and galactose were ranged 67 - 73% and 28 - 33%, respectively. Ratio of mannose to galactose is 2:1. Keyword: Guar, e ndosperm, m annose and g alactose. Introduction Guar seed ( Cyamopsis tetragonoloba ) composed of 30 - 33% hull, 27 - 30% endosperm and 43 - 47% germ. The germ and hull of the guar seeds are known as guar meal, which rich in protein, hence used for the cattle feed. The germ has toxic effect but recently advanced research has been made on the germ to reduce its toxic effect and to make it suitable for animal consumption as a rich source of the protein 1 . The endosperm is commercially important part in the guar seed, as it is converted into powder gum. It contains 41% dry weight and acetone insoluble solids of the seed. At least 75% of acetone insoluble solids of the endosperm are galactomannose and 12% being accounted for as pentosan, protein, pectin, phytin, ash and dilute acid insoluble residue 2. The guar crop is acquired an economic imp ortance after the discovery of the gummy substance ( g alactomannan) in its endosperm 1 . Galactomannan are composed of 1 – 4 mannanose ba ckbone with varying degree of 1 - 6 galactose substitution and are found in the cell wall of legume endosperm 3 . Guar se eds are a rich source of mucilage or gum which forms a viscous gel in cold water and used as an emulsifier, thickener, stabilizer in a wide range of food and industrial application 4 . Guar galactomannan has mannose to galactose ( M:G) ratio of 6:1 5 . The p ure mannanose without galactose is completely insoluble in the water, but increasing of galactose substitution in guar gum increase the solubility of the polymer by allowing it to become attended 6 . The mannose to galactose ratio is 2:1, guar gum is insolu ble in organic solvent, molecular weight range is 50.000 – 80.000 and gum is a white to yellowish white, nearly odorless, free flowing powder with a bland taste 7 . Objectives of this study are estimated the proximate analysis, physical characters, mineral s contents, mannose, galactose, ratio of mannose: galactose and tannin content of endosperm for six selected guar genotypes grown in Sudan. Materials and methods Sample Preparation : Six guar genotypes (X 1 H 6 , X 1 H 7 , X 2 H 0 , X 2 H 4 , X 2 H 6 and X 2 H 8 ) were collected from the Department of Agronomy, Faculty of Agriculture, University of Khartoum, Sudan. The seeds of the six guar genotypes were soaked in water for 12 hours separately and then hand pounded to separate the endosperm from the hull and germ . The separated endosperms were then dried at 105 o C for 20 minutes and then ground to pass 0.2 mm screen and finally, it is kept in polyethylene bag till start the chemical analysis. Physical and Chemical methods : Refractive indices, specific rotation, relative viscously, pH value, optical density, protein, ether extract, ash, and fiber contents were determined as described by Noble et al. 8 , but . Carbohydrates was determined by difference and moisture content was measured according to Patil et al. , 9. Ash composition : Minerals contents of endosperm were extracted according to method described by Pearson 10 . The measurement of minerals was done by using atomic absorption as described by Nwajej et al ., 11 . ISCA Journal of Biological Sciences _________________ ______________________________ ______ __ _ _ ISCA J. Biological Sci. Vol. 1 ( 1 ), 67 - 7 0 , May (201 2 ) International Science Congress Association 68 Total available carbohydrates : Total available carb ohydrates content of endosperms were determined as described by Clegg 12 . 100mg of galactose were dissolved in 100 ml distilled water (1mg = 10 ml). Then 10 ml of strong galactose solution was dissolved in 100 ml distilled water to make the dilute galactos e solution. The same procedure was done to make the dilute mannose 100 mg a nthrone (0.1%): was dissolved in 100 ml sulphuric acid (270 ml Con. H 2 SO 4 was dissolved in 300 ml distilled water). One ml from each dilute galactose, mannose and sample was pipette d into a series of test tubes 1, 2, and 3, respectively. Then 5 ml of the Anthrone reagent was added to each test tube, then the content of each test tube was heated in water bath for 12 minutes and allow cooling to room temperature. Spectrophotometer was set up at 360 nm, so that the scale read zero with distilled water. Then the dilute galactose and mannose and sample were read. CHO as galactose ( or mannose) % = 25 X B S X A w here : B = r eading of sample, A = r eading of dilute galactose (or mannose) and S = w eight of origin sample Tannin content: Quantities estimation of tannin for each separated endosperm was carried out using the modified vanillin - HCL in methanol method as descri bed by Price and Butler 13 . A standard curve was prepared expressing the results as c atechin equivalent i.e. amount of the c atechin (mg/ml) which gives a colour intensity equivalent to that given by tannins after correction of the blank. Statistical analys is : A test of homogeneity for error variance for each variable was done according to Gomez and Gomez 14. Results and discussion Proximate analysis : Table - 1 showed Moisture content of endosperm is ranged from 4.8 – 8.7%, which is higher than those range reported by Thomas 15 and lower than those given by 16 . Protein content is ranged 3.5 – 5.0%.which is agreement with those results given by 15 .Ether extract (fat) of endosperm is ranged from 0.5 – 0.9%, which within the range reported by 4 . The ash content is ranged from 0.5 – 0.8%, which falls within range reported by Stein and Hall 16 . Fiber contents are ranged from 1.4 – 2.0%, which is online with those ranges given by 16 . Carbohydrates contents are varied from 83.3 – 87.5%, which is higher than those values reported by Thomas 15 . The results revealed that there is highly significant difference in moisture, protein, ether extract, ash and carbohydrates content, but there is no significant difference in crude fiber at level (p≤0.05) Physical characters : Table - 2 represented mea n values of refractive indices are 1.2337 for overall samples at Con. 0.1mg/ 100 ml. Relative viscously of endosperm ranged from 0.20 – 0.47 (H 2 O used as solvent) and varied from 0.37 – 0.65 (4% NaCl used as solvent). It was found that relative viscously of 4% NaCl is higher than those of distilled water. These findings indicated that the relative viscosity is affected by the types of solvents. The pH values varied from 5.0 – 7.0, which fell within range reported by 17 . Specific rotation ranged from + 20 to + 76. Optical density ranged from 0.035 – 0.050. The results revealed that there is significantly difference in relative viscously (in both distilled water and 4% NaCl), pH value, specific rotation and optical density at level (p ≤0.05). Ash compositio n : Table - 3 showed mean value of Potassium ranged from 57 – 79 mg /Kg. Sodium content varied from 242 – 755 mg/Kg. Calcium mean ranged from 11 – 24 mg/Kg,. Iron content varied from 49 – 287 mg/Kg. Magnesium content varied from 2.5 – 13 %. The mean values of Phosphorus ranged from 15.5 – 22. %.The finding indicated that there is highly significant difference in Na, Mg and Fe, significant difference in Ca and no significant difference in K and P at level (P ≤ 0.05) Total available Carbohydrates and tannin contents : Table - 4 represented the total available carbohydrates as mannose is ranged from 67 – 73% while the total available carbohydrates as galactose are ranged from 28 – 33%. These results indicated that the mannose to galactose ratio is 2: 1, which is similar to those values given by Yoko 7 , but it is differing to value given by Edwards 5 . The tannin content is ranged from 445 – 450 mg/100g. The similar results were reported for guar seeds soaked in water for different time intervals 18 . In addition to th at there is no significant difference in tannin content at level (P≤0.05). Table - 1 Pro ximate analysis of endosperm (Guar gum) of six guar genotypes CHO % Fiber % Ash % Fat % Protein % Moisture % Parameters 87.5 1.5 0.5 0.5 3.5 6.5 X 1 H 6 87.3 1.4 0.5 0.9 4.5 7.4 X 1 H 7 87.3 1.9 0.8 0.5 4.4 4.8 X 2 H 0 83.3 2.0 1.3 0.7 4.0 8.7 X 2 H 4 83.8 1.9 0.8 0.7 5.0 7.8 X 2 H 6 84.6 1.4 1.0 0.7 5.5 6.8 X 2 H 8 71.9 1.7 0.8 10.7 4.5 7.0 Mean 1.9 0.27 0.30 0.15 0.7 1.3 SD * Each value is average of three replicates basis on dry weight ISCA Journal of Biological Sciences _________________ ______________________________ ______ __ _ _ ISCA J. Biological Sci. Vol. 1 ( 1 ), 67 - 7 0 , May (201 2 ) International Science Congress Association 69 Table - 2 Physical characters of endosperm (Guar gum) of six guar genotypes Parameters Refractive index Relative viscously pH Optical density Specific rotation H 2 O 4% NaCl X 1 H 6 1.2337 0.47 0.42 5 0.035 + 36 X 1 H 7 1.2337 0.29 0.65 5 0.035 + 76 X 2 H 0 1.2337 0.33 0.45 5 0.035 + 59 X 2 H 4 1.2337 0.25 0.37 7 0.050 + 75 X 2 H 6 1.2337 0.47 0.64 6 0.040 + 17 X 2 H 8 1.2337 0.20 0.45 5 0.040 + 28 Mean 1.237 0.34 0.50 5.5 0.039 48.5 SD 0 0.11 0..11 0.83 0.005 25 * Each value is average of three replicates basis on dry weight Table - 3 Ash composition of endosperm (K, Na, Ca, Fe, Mg and P ) of six guar genotypes Parameters K (mg/Kg) Na (mg/Kg) Ca (mg/Kg) Fe (mg/Kg) Mg % P % X 1 H 6 70 491 42.0 100 0.06 0.03 X 1 H 7 84 755 11.0 196 0.06 0.17 X 2 H 0 84 491 11.0 100 0.02 0.14 X 2 H 4 57 642 11.0 279 0.03 0.14 X 2 H 6 70 566 34.0 287 0.09 0.13 X 2 H 8 79 415 11.0 113 0.02 0.14 Mean 74 560 20 179.2 0.04 0.13 SD 10.4 122.7 14.17 88.0 0.02 0.04 * Each value is average of three replicates basis on dry weight Table - 4 Mannose, Galactose, Ration of M:G and tannin content of endosperm of six guar genotypes Parameters Mannose (M) % Galactose (G) % Ratio M:G Tannin % X 1 H 6 70 30 2:1 4.5 X 1 H 7 71 33 2:1 4.5 X 2 H 0 67 33 2:1 4.5 X 2 H 4 73 28 2:1 4.3 X 2 H 6 70 30 2:1 4.5 X 2 H 8 71 29 2:1 4.5 Mean 70.33 30.5 2:1 4.5 SD 1.96 2.07 -- 0 ISCA Journal of Biological Sciences _________________ ______________________________ ______ __ _ _ ISCA J. Biological Sci. Vol. 1 ( 1 ), 67 - 7 0 , May (201 2 ) International Science Congress Association 70 Conclusion It is concluded that the variation in chemical, physical, ash composition, total available carbohydrate and tannin content is controlled by genetic or environment factors under which plant material were tested Acknowledgement Authors extremely indebted to the soul of Dr. Karmalla K.A., Department of Food Science and Technology, Faculty of Agriculture, University of Khartoum, Sudan, to whom we express our enormous gratitude for his patience continues guidance, meticulous and fundamental throughout this study. References 1. Murwan K . S . and Abdalla A . H. , Yield and Yield Components of Forty Five Guar ( Cyamopsis tetragonoba ) Genotypes Grown in Sudan , Nile Basin Research Journal , 11(4) , 48 - 54 (2008) 2. John H . M . , William G . C . and Herman F . W. , The Role of the Endosperm in the Germination of Legumes: Galactomannan, Nitrogen, Phosphorus Change in the Germination of Guar ( Cyamopsis tetragonoba; Leguminosae) , American Journal of Botany , 63(6), 790 – 797 (1976) 3. Marten J . J . and Brunstedt J. , In vivo - modification of the cell wall polysaccharide galactomannan of guar transformed with a glycosidase gene from Senna , Molecular Breeding 7 , 211 – 219 (2001) 4. Marina N . , Jerez I . T . , J.ihe S . , Zhao P . X . , Dixon RA and May GD , Analysis of cDNA librarie s from developing seeds of guar ( Cyamopsis tetragonoba (L. ) Taub) , BMC Plant Biology 7 , 62 (2007) 5. Edwards M . E . , Scot C . , Gidley M.J . and Reid J . S. , Control of mannose/galactose during galactomannan formation in developing legume Seeds , Planta , 187 , 67 - 74 (1992) 6. Noble O . , Perez D . , Rochas C . and Travel F. , Optical rotation of branched polysaccharides , Polymer Bulletin, 16 , 175 - 180 (1989) 7. Yoko K. , Guar Gum, Chemical Technical Assessment (CTA) , 1 – 4 Ph.D. Thesis, 69TH JECFA (2008) 8. Association of Official and Analytical Chemists , (A.OAC) , Official Methods of Analysis 15 th ed., Washington, D.C. (1990) 9. Patil M.M., Kalse S.B. and Jain S.K. , OSMO - Convective drying of Onion Slices , Res. J. Recent Sci. , 1(1), 51 - 59 (2012) 10. Egon H ., Kirk R.S., Pearson D. , The Chemical Analysis of Food , Sawyer, New York (1980) 11. Nwajej G,E., Okwagi P., Nwajej R.L. and Obi - Lyeke G.E. , Analytical Assessment of Trace Element in Soil, Tomato, Leaves and Fruit in the Vicinity of paint industry, Nigeria , 1(4), 22 - 26 (2012) 12. Clegg K . M. , In total available carbohydrates (Anthrone method) , J. Sci. Agric , 7 , 40 (1958) 13. Price M . L . and Butler L . C. , Tannin and Nutrition , Adriculture Experiment Station , Purdue University, West Lafayette , Indian (1980) 14. Gomez T . P . and Gomez A . A. , Statistical Procedure for Agriculture Research , John Wiley and Sons Inc. , New York, USA (1984) 15. Thomas T . A . , Dabas BS and Chopra D . D ., Guar gum has many uses , Indian Farming , 32(4) , 7 – 10 (1980) 16. Stein and Hall Co. , Jaguar guar gum Stein, Hall and Co, New York ( 1962 ) 17. Whistler R . L. , Guar gum, Locust bean, and others , In : Natural Plant Hydrocolloids , 45 – 50 (1954) 18. Majed B . A . , Rashed A . H . , Mohamed E . A . , Amro B . H . and Elfadil E . B. , Proximate Composition, Ant - nutritional Factors and Protein Fractions of Guar Gum Seeds as influenced by Processing Treatment , Pakistan Journal of Nutrition , 5(5) , 481 - 484 (2006)