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Guar Gum
Guar Gum also known as guaran is a natural
polymer derived from the ground guar bean (endosperm of Cyamopsis Tetragonolobus),
a plant of the Leguminosae family.
Manufacturing Process
The Guar Seed is broken to get 2 halves referred to as Guar splits.
Dehusking of the splits is achieved through heating, grinding, polishing and
sieving. The endosperm is separated from the germ through sieving and is
then hydrated, pulverised and dried to make a powder. |
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Chemically, guar gum is a polysaccharide composed of the sugars galactose
and mannose. The backbone is a linear chain of β 1,4-linked mannose residues
to which galactose residues are 1,6-linked at every second mannose, forming
short side-branches.
Solubility and viscosity
Guar gum is more soluble than locust bean gum and is a better emulsifier as
it has more galactose branch points. Unlike locust bean gum, it is not
self-gelling.[4] However, either borax or calcium can cross-link guar gum,
causing it to gel. In water it is nonionic and hydrocolloidal. It is not
affected by ionic strength or pH, but will degrade at pH extremes at
temperature (e.g. pH 3 at 50°C). It remains stable in solution over pH range
5-7. Strong acids cause hydrolysis and loss of viscosity, and alkalies in
strong concentration also tend to reduce viscosity. It is insoluble in most
hydrocarbon solvents.
Guar gum shows high low-shear viscosity but is strongly shear-thinning. It
is very thixotropic above concentration 1%, but below 0.3% the thixotropy is
slight. It has much greater low-shear viscosity than that of locust bean
gum, and also generally greater than that of other hydrocolloids. Guar gum
shows viscosity synergy with xanthan gum. Guar gum and micellar casein
mixtures can be slightly thixotropic if a biphase system forms.
Thickening
Guar gum is economical because it has almost 8 times the water-thickening
potency of cornstarch - only a very small quantity is needed for producing
sufficient viscosity. Thus it can be used in various multi-phase
formulations: as an emulsifier because it helps to prevent oil droplets from
coalescing, and/or as a stabilizer because it helps to prevent solid
particles from settling.
Ice-crystal growth
Guar gum retards ice crystal growth non-specifically by slowing mass
transfer across the solid/liquid interface. It shows good stability during
freeze-thaw cycles.
Miniscience
produces a wide range of chemicals for research and educational uses. |
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Distributors of scientific and educational products
Where to buy?
Most pictures are linked to
the pricing and online store for fast and convenient ordering
Our products are available at the following
online stores. For large orders please call in advance and verify the
availability, wholesale discounts and shipping options. If you cannot find any
product in the online store of your choice, please use the search option of the
store or call (973)777-3113 for further assistance.
All orders will be shipped from our
warehouse in United States (USA). We ship worldwide
to most countries including U.S., Canada, Australia, United Kingdom, New
Zealand, Germany, France, Netherlands, and many other countries.
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List of metals for science experiments
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