- Guar
-
Guar 
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/guwar/guvar bean or cluster bean (Cyamopsis tetragonoloba) is an annual legume and the source of guar gum. It grows best under conditions with frequent rainfall, but tolerates arid conditions well.[1] About 80% of world production occurs in India, but, due to strong demand, the plant is being introduced into new areas. It is known as गवार् gawaar in Hindi and Marathi, గోరు చిక్కుడు goruchikkudu kaya or gokarakaya in Telugu, gorikayie in Kannada, and kotthavarai (கொத்தவரைக்காய்) in Tamil.
Contents
Cultivation
For best growth, the guar bean requires full sunshine, flashing rainfalls that are moderately frequent, and well-drained soil. However, it is extremely drought-tolerant and thrives in semiarid regions. Too much precipitation can cause the plant to become more "leafy", thereby reducing the number of pods and/or the number of seeds per pod that affects the size and yield of seeds. The crop is sown after the first rains in July and harvested in late October. It is grown principally in northwestern India, and Pakistan,punjab mianwali harnoli[2] with smaller crops grown in the semiarid areas of the high plains of Texas in the USA,[3] Australia and Africa. The most important growing area centres on Jodhpur in Rajasthan, India.
Currently, India is the source of about 80% of the world production of guar gum. Several commercial growers[4] have converted their crops to guar production to support the increasing demand for guar and other organic crops[5] in the United States.
Varieties: Pusa Naubahar and Pusa Sadabahar. Seeds at the rate of 10 to 12 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).
Uses
Agriculture
Guar can be fed to cattle, or used as a green manure.
Food
Guar can be eaten as a green bean, but is more important as the source of guar gum. Guar beans have a large endosperm that contains galactomannan gum, a substance which forms a gel in water. This is commonly known as guar gum and is used in dairy products like ice cream and as a stabilizer in cheese and cold-meat processing.
Another use is as a fiber supplement. After being partially hydrolyzed, guar gum is completely soluble in water and soft food. Being approximately 75% dietary fiber, it allows fiber to be added to a food with a minimal effect on taste and texture.
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. 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 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.
Industrial uses
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 of oil and gas formations. 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 linear gel that does not block the formation and helps efficiently in formation cleaning process. The borate - guar reaction is reversible, and depends on the pH (hydrogen ion concentration) of the solution. Crosslinking of guar with borate happens at high pH (approximately 9-10) of solution. Guar gum has also proven a useful substitute for locust bean gum (made from carob seeds).
Sugaring paste used for epilation may include guar as an ingredient.[6]References
- ^ "Guar Gum" - Agro Gums
- ^ " Guar Gum". Midwest Herbs
- ^ "Guar Production" Vernon Agricultural Research & Extension Center, Texas A&M Univ. 2006.
- ^ "large scale guar growers"
- ^ "organic fertilizer crops"
- ^ Studio Smooth website. Accessed April 11, 2009.
Scientific literature
- Overbeeke N, Termorshuizen GH, Giuseppin ML, Underwood DR, Verrips CT (May 1990). "Secretion of the alpha-galactosidase from Cyamopsis tetragonoloba (guar) by Bacillus subtilis". Appl. Environ. Microbiol. 56 (5): 1429–34. PMC 184423. PMID 2160224. http://aem.asm.org/cgi/pmidlookup?view=long&pmid=2160224.
- Bergkamp RJ, Kool IM, Geerse RH, Planta RJ (April 1992). "Multiple-copy integration of the alpha-galactosidase gene from Cyamopsis tetragonoloba into the ribosomal DNA of Kluyveromyces lactis". Curr. Genet. 21 (4–5): 365–70. doi:10.1007/BF00351696. PMID 1326415.
- GOPALA RAO P, C. DAMODARA REDDY and J. K. RAMAIAH (1987). "Effect of B Vitamins on the Protein Component of Clusterbeans Cyamopsis tetragonoloba (L.) Taub". Annals of Botany 59 (3): 281–4. http://aob.oxfordjournals.org/cgi/content/abstract/59/3/281.
External links
Categories:- Faboideae
- Edible legumes
Wikimedia Foundation. 2010.
