Guar gum:Guar gum comes from the en

Guar gum:
Guar gum comes from the endosperm of the seed of the
legume plant Cyamopsis tetragonolobus. Guar gum is
prepared by first drying the pods in sunlight, then manually
separating from the seeds. The gum is commercially extracted
from the seeds essentially by a mechanical process of
roasting, differential attrition, sieving and polishing. The
seeds are broken and the germ is separated from the
endosperm. Two halves of the endosperm are obtained from
each seed and are known as undehusked Guar Splits. Refined
guar splits are obtained when the fine layer of fibrous
material, which forms the husk, is removed and separated
from the endosperm halves by polishing. The refined Guar
Splits are then treated and finished into powders by a variety
of routes and processing techniques depending upon the end
41 product desired .
Chemically, guar gum is a polysaccharide composed of the
sugars galactose and mannose. The backbone is a linear chain
of ! 1,4-linked mannose residues to which galactose residues
are 1,6-linked at every second mannose, forming short side-branches .
Guar gum is more soluble than locust bean gum and is a better
emulsifier as it has more galactose branch points. It degrades
43 at extremes of pH and 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.