Guar gum is a natural seed product used for many applications in the food industry, oil field chemicals and the textile industry.
The product has been extensively applied as a thickener, emulsifier and stabilizer all over the world. The usage of this product as food additives in these markets has resulted to detailed analysis to determine its effects and also regulate the quality of the produce, manufacturing process, possible uses in food additive, chemical characterization, and reaction with other foods.
Authorization by regulatory bodies
Currently, Guar is an authorized products for use as a food additive in the European Union as stipulated by the European parliament and council directive 95/2/EC. The product holds a “not limited” directive which was issued in 1975 by joint forum by food and agriculture organization (FAO) and world health organization (WHO) in the Joint Expert Committee on Food Additives (JECFA). Various bodies such as European Food Safety Authority (EFSA) and other food safety bodies in the world have also approved this product.
Recommendation for use as food additive
Various food standardizing bodies specify different attributes as listed below
Product definition: safety standards specify that the additive or flour should be derived from ground endosperm of the plant Cyamopsis tetragonaloba (L) Taub. (syn. Cyamopsis psoraloides). This additive should have a molecular weight between 50,000-8,000,000g/mol polysaccharides that comprise of galactomannans. Galactomannans are polysaccharide units made up of galactopyranose and mannopyranose and should have a mannose: galactose ratio of about 2:1.
Physical description: It should be white, or yellow white. It has no odour, is free flowing and has bland taste.
Chemical characterization: additives should have the following chemical structure
Manufacturing process: food specification indicate that the gum is obtained after separating husk and germ. The hull removed through heat treatment and milling. This is followed by sieving and clarification. The detailed manufacturing process for food grade guar approved by FAO, EFSA and other regulating bodies is shown below
Purity tests: recommended purity tests are solubility tests using ethanol, gel formation tests using sodium borate, gum constituents tests using 100mg of the sample and 1-10 µL of hydrolysate to identify galactose and mannose, examining using a microscope.
Uses as food additives
FAO, EFSA and JECFA specify that the guar gum suitable as and emulsifier in food because of its compatibility with plant hydrocolloids. In the USA, Europe and other countries; guar is specified as an emulsifier in various foods industries. The maximum use in percentage as a food additive are specified below
|Food industry (Additive)||Maximum allowed quantity (%)|
|Baked products and mixes||0.35|
|Cereals for breakfast||1.2|
|Cooking fat and oils||2.0|
|Jam and jellies||1.0|
|Vegetable and vegetable juice||2.0|
|Sweet sauce and syrup||1.0|
Source FAO, (2008). 69th JEFCA conference, chemical and technical assessment for Guar gum.
As a stabilizer and thickening agent, the maximum additive levels are baked goods (0.2%), cheese (0.14%) and ice cream (0.1-0.3%). Various food safety organizations have also approved the use of partial depolymerisation through heat treatment and hydrolysis to result to particles with lower molecular size and varying viscosity.