(Cyamopsis tetragonoloba – Family Leguminosae)
Cluster bean, guar gum
The guar gum bean grows on upright bushy plants that probably originated in Africa and have been cultivated since time immemorial in India and Pakistan. They were grown mainly as a food crop for animals and as green manure.
The pods grow in groups, looking something like small bunches of bananas. They are two to four inches long, straight and pencil-like, with a long, tapering point and standing upright when ripe.
They contain five to twelve pea-sized seeds. The pods are produced along a vertical stem like soybeans and can be harvested with a grain harvester.
The plant is now cultivated in the US Southwest, mainly in Texas and Oklahoma.
Both the pods and the seeds must be thoroughly cooked before eating. They can be eaten like French beans or added to curries.
In the 1950s, it was discovered that the bean yielded a gum which became valuable to the food industry as an emulsifier, thickener, and stabalizer. It is a must to include when baking with gluten-free flour.
It has since been used in everything from ice cream to postage stamp glue, as well as in paper production, textile printing pastes, cosmetics, and pharmaceuticals.
It has the thickening power almost eight times that of cornstarch.
Guar gum is a galactomannan, similar to the locust bean gum, and obtained by processing the seeds of the annual forage crop. The endosperm is milled into a flour, which is then reconstituted for use.