Guar

Guar Cyamopsis tetragonoloba
Guar bean cluster
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fabales
Family:	Fabaceae
Genus:	Cyamopsis
Species:	C. tetragonoloba
Binomial name
Cyamopsis tetragonoloba (L.) Taub.
Synonyms
Cyamopsis psoralioides L.

The Guar or cluster bean, with the botanical name Cyamopsis tetragonoloba, is an annual legume and the source of guar gum. It is also known as Gavar, Guwar or Guvar bean.

The origin of Cyamopsis tetragonoloba is unknown, since it has never been found in the wild.^[1] It is assumed to have developed from the African species Cyamopsis senegalesis. It was further domesticated in India and Pakistan, where it has been cultivated for many centuries.^[2] Guar grows well in semiarid areas, but frequent rainfall is necessary.

This legume is a very valuable plant within a crop rotation cycle, as it lives in symbiosis with nitrogen-fixing bacteria.^[3] In fact, agriculturists in semi-arid regions of Rajasthan follow crop-rotation and use guar as a source to replenish the soil with essential fertilizers and nitrogen fixation, before the next crop. Guar as a plant has a multitude of different functions for human and animal nutrition but its gelling-agent-containing seeds (guar gum) are today the most important use.^[2] Demand is rising rapidly due to industrial use of guar gum in hydraulic fracturing (oil shale gas).^[2] About 80% of world production occurs in India and Pakistan, but due to strong demand, the plant is being introduced into new areas.

Biology

Cyamopsis tetragonoloba grows upright, reaching a maximum height of up to 2–3 m. It has a main single stem with either basal branching or fine branching along the stem. Thanks to taproots, the guar plant can access soil moisture in low soil depths.^[3] Additionally, this legume develops root nodules with nitrogen-fixing soil bacteria rhizobia in the surface part of its rooting system. Its leaves and stems are mostly hairy, dependent on the cultivar. Its fine leaves have an elongated oval shape (5 to 10 cm length) and of alternate position. Clusters of flowers grow in the plant axil and are of white to blueish color. The developing pods are rather flat and slim containing 5 to 12 small oval seeds of 5 mm length (TGW = 25-40 g). Usually, mature seeds are white or gray, but in case of excess moisture they can turn black and lose germination capacity. The chromosome number of guar seeds is 2n=14.^[4] The seeds of guar beans have a very remarkable characteristic. Its kernel consists of a protein-rich germ (43-46%) and a relatively large endosperm (34-40 %), containing big amounts of the galactomannan.^[2] The latter is polysaccharide containing polymers of mannose and galactose in a ratio of 2:1 with many branches.^[5] Thanks to the latter, it exhibits a great hydrogen bonding activity ^[1] having a viscosifying effect in liquids.

Cultivation

Climate Requirements

Guar is very drought-tolerant and sun-loving, but it is very susceptible to frost.^[1] Even though it can cope with little but regular rainfall, it requires sufficient soil moisture before planting and during maturation of seeds.^[6] Frequent drought periods can lead to delayed maturation.^[3] On the contrary, too much moisture during early phase of growth and after maturation lead to lower seed quality.^[1] Guar is also produced near to coastal areas in the Gandhidham region of Kutch, Gujarat, India.

Soil Requirements

Cyamopsis tetragonoloba (L.) can grow on a wide range of different soil types. Preferably in fertile, medium-textured and sandy loam soils that are well-drained because waterlogging decreases plant performance. In respect of soil acidity, guar grows best in moderate alkaline conditions (pH 7-8) and is tolerant of salinity. Thanks to its taproots which are inoculated with rhizobia nodules, it produces nitrogen-rich biomass and improves soil quality.^[3]

Cultural Practices

,^[3][4]

Seeding	Seedbed: firm, weed-free Date: soil temperature > 21 °C (optimum: 30 °C); monsoon-regions: after first rain event in June or early July Rate: seed use: 10–30 kg/ha, biomass use: 50–100 kg/ha Row spacing: seed use: 45–60 cm, biomass use: 30–45 cm
Fertilizer	Nitrogen: not necessary Phosphorus: often limiting, US: Superphosphate 200–250 kg/ha
Plant Protection	Weeding: young guar plants development is very susceptible to weed concurrence; well and early prepared seedbeds help to reduce weed pressure Diseases: choose disease-resistant cultivars, 2 major diseases: Alternaria cucumerina var. cyamopsidis and Xanthomonoas cyamopsidis Predators: Contarinia texana guar midge: rainfall or sprinkler irrigation reduce midge populations
Harvest	seed pods: dry, brown, 60–90 days after sowing; biomass: first lower pods turn brown
Yield	seeds: 5-8 dt/ha; biomass: 40-50 t/ha

Cultivation Areas

It is grown principally in north-western India and Pakistan^[7] with smaller crops grown in the semiarid areas of the high plains of Texas in the US,^[8] Australia and Africa. The most important growing area centres on Jodhpur in Rajasthan, India where demand for guar for fractionation produced an agricultural boom as in 2012.^[9] Currently, India and Pakistan are the main producers of cluster bean, accounting for 80% production of the world's total, while Thar, Punjab Dry Areas in Pakistan and Rajasthan, Gujarat, Kutch region occupies the largest area (82.1%) under guar cultivation in India. In addition to its cultivation in India and Pakistan, the crop is also grown as a cash crop in other parts of the world.^[10] Several commercial growers^[11] have converted their crops to guar production to support the increasing demand for guar and other organic crops ^[12] in the United States.

Varieties

Pusa Naubahar and Pusa Sadabahar. Seeds at the rate of 30 kilograms/hectare (9–11 lb/acre) are planted at a spacing of 45-60 x 20–30 cm (18–24 x 8–12 in) in February–March and June–July. During rainy season, the seeds are sown 2–3 cm (~1 in) deep on ridges and in furrows during summer months. FYM is applied at the rate of 25 tonnes/ha (11.1 tons/acre). N, P2O5 and K2O recommendation for the crop is 20:60:80 kg/ha (18:53:71 lb/acre). Average yield is 5 to 6 tonnes/ha (2.2–2.6 tons/acre). Meager information is available for genetic variability in clusterbean addressing the qualitative traits (Pathak et al. 2011)^[13]

Uses

Guar plant

Agriculture

• Forage: Guar plants can be used as cattle feed, but due to hydrocyanic acid in its beans, only mature beans can be used.^[1]
• Green manure: Guar plantings increase the yield of subsequent crops as this legume conserves soil nutrient content.^[1]

Domestic use

• Vegetable: Guar leaves can be used like spinach and the pods are prepared like salad or vegetables.^[4] Its beans are very nutritious but the guar protein is not usable by humans unless toasted to destroy the trypsin inhibitor.

Guar gum

As mentioned in the biology section, the seeds of the guar bean contain a very large endosperm. This endosperm consists of a very large polysaccharide of galactose and mannose. This polymer is water-soluble and exhibits a viscosifying effect in water. Guar gum has a multitude of different applications in food products, industrial products, and extractive industry.

Food

In several food and beverages guar gum is used as additive in order to change its viscosity or as fiber source.

Food	Function
Baked goods	Dough improver [14]
Cheese	Texture improver [15]
Ice Cream	Smaller ice crystals [16]
Fried Products	Oil uptake reduction [17]

Partially hydrolyzed guar gum (PHGG) is produced by the partial enzymatic hydrolysis of guaran, the galactomannan of the endosperm of guar seeds (guar gum). It is a neutral polysaccharide consisting of a mannose backbone chain with single galactose side units occurring on almost two out of every three mannose units. The average molecular weight is about 25,000 Daltons. This gives a PHGG that still assays and functions as a soluble dietary fiber.

PHGG as sold commercially is completely soluble, acid and heat stable, unaffected by ions, and will not gel at high concentrations. Commercial PHGG is approximately 75% dietary fiber and has minimal effect on taste and texture in food and beverage items. PHGG is fully fermentable in the large bowel, with a high rate of volatile fatty acid formation. The pH of the feces is lowered along with an increase in fecal bulk that mainly consists of bacterial cell mass and water. Clinical studies have demonstrated a prebiotic effect of PHGG. Studies have also shown that PHGG can be used to maintain regularity. PHGG is used in foods for particulate suspension, emulsification, antistaling, ice crystal control, and reduced fat baked goods.

Gawar Phali With Aaloo (Guar Bean With Potatoes)

Industry

Derivatives of guar gum that has been further reacted is also used in industrial applications, such as the paper and textile industry, ore flotation, the manufacture of explosives and hydraulic fracturing (fracking) of oil and gas formations.^[9][18] Guar gum is often crosslinked with boron or chromium ions to make it more stable and heat-resistant. The crosslinking of guar with metal ions results in a gel that does not block the formation and helps efficiently in formation cleaning process. Guar and its derivatives make gel complexes with ions of Aluminium, Zirconium, Titanium, Chromium and Boron.^[19] The borate–guar reaction is reversible, and depends on the pH (hydrogen ion concentration) of the solution. Crosslinking of guar with borate occurs at high pH (approximately 9–10) of the solution. Guar gum has also proven a useful substitute for locust bean gum (made from carob seeds).

Feeds

Guar meal korma and Guar meal Churi are widely used as prime raw material for Producing various kinds of Cattle feeds, Aqua feeds, Fish feeds, Poultry Feeds, Dairy feeds, Swine feeds etc.

Fracking agent

Through the use of guar gum in the hydraulic fracturing (fracking) extraction of oil and shale gas, the demand has increased substantially. Only 10% of the Indian production stays within the country and the remaining 90% is exported for shale gas and oil industries. Consequently, many former cotton or wheat fields are converted into guar fields as production costs are also lower. But the increase of guar gum prices also has other reasons.^[20] But since prices are lower the farmers stop harvesting the Guar and returned to cotton & cumin and sesame crops sowing.

Further reading

• Pathak, Rakesh: Clusterbean: Physiology, Genetics, and Cultivation. Springer, Singapore 2015, ISBN 978-981-287-905-9
• Web page ( Provides latest update on guar free of cost) www.guargumcultivation.com

References

1. Whistler R.L. and Hymowitz T. 1979. Guar: agronomy, production, industrial use and nutrition. Purdue University Press, West Lafayette
2. Mudgil, D.; Barak, S.; Khatkar, B. S. (2011). "Guar gum: Processing, properties and food applications—A Review". Journal of Food Science and Technology. doi:10.1007/s13197-011-0522-x.
3. Undersander D.J., Putnam D.H., Kaminski A.R., Doll J.D., Oblinger E.S. and Gunsolus J.L. 1991. Guar. University of Wisconsin-Madison, University of Minnesota Accessed November 8, 2012.
4. "Guarbohne (Cyamopsis tetragonolobus [L.] Taub. [=C. psoralioides DC.])" Accessed November 8, 2012.
5. Garti N. and Leser M.E 2001. Emulsification properties of hydrocolloids. Polymers for Advanced Technologies 12: 123-135.
6. Anderson E. 1949. Endosperm mucilages of legumes: occurrences and composition. Industrial and Engineering Chemistry Research 41:2887-2890.
7. " Guar Gum". Midwest Herbs
8. "Guar Production" Vernon Agricultural Research & Extension Center, Texas A&M Univ. 2006.
9. Gardiner Harris (July 16, 2012). "In Tiny Bean, India’s Dirt-Poor Farmers Strike Gas-Drilling Gold". The New York Times. Retrieved July 17, 2012.
10. Pathak, R.; Singh, S. K.; Singh, M.; Henry, A. (2010). "Molecular assessment of genetic diversity in cluster bean (Cyamopsis tetragonoloba) genotypes". Journal of Genetics 89 (2): 243–246. doi:10.1007/s12041-010-0033-y. PMID 20861578.
11. "large scale guar growers"
12. "organic fertilizer crops"
13. Pathak, R., Singh, M. and Henry, A. 2011. Genetic diversity and interrelationship among clusterbean (Cyamopsis tetragonoloba) for qualitative traits. Indian Journal of Agricultural Sciences 81(5):402-406.
14. Kohajdova Z. and Karovicova J. 2008. Influence hof hydrocooloids on quaality of baked goods. ACTA Scientiarum Polonorum Technologia Alimentaria 7:42-49.
15. Klis J.B 1966. Woody's Chunk O'Gold cold-pack chees food weeps no more. Food Processing Marketing 27:58-59.
16. Sutton R.L. and Wilcox J. 1998. Recrystallization in ice cream as affected by stabilizers. Journal of Food Science 63:104-107.
17. Sakhale B.K. Badgujar J.B., Pawar V.D. and Sananse S.L. 2011. Effect of hydrocolloids incorporation in casing of Samosa on reduction of oil uptake. Journal of Food Science doi:10.1007/s13197-011-0522-x.
18. NY Times
19. "Guar gum derivatives". Chemtotal. Retrieved 3 March 2013.
20. Accessed November 8, 2012