4.4 Polysaccharides 311(4.143)As a result of the strong cross-linkage, this
polysaccharide is insoluble in water and resistant
to enzymes and microorganisms. However, it
swells greatly even in cold water. Suspensions
have a pasty consistency at concentrations of
more than 3%.
4.4.4.8.3 Utilization
Karaya gum is used as a water binder (soft
cheese), a binding agent (meat products like
corned beef, sausages), a stabilizer of protein
foams (beer, whipped cream, meringues), and as
a thickener (soups, sauces, salad dressings, may-
onnaise, ketchup). It increases the freeze-thaw
stability of products, prevents synaeresis of gels,
and provides “body”.
4.4.4.9 GuaranGum
4.4.4.9.1 Occurrence,Isolation
Guar flour is obtained from the seed endosperm of
the leguminous plantCyamopsis tetragonoloba.
The seed is decoated and the germ removed. In
addition to the polysaccharide guaran, guar flour
contains 10–15% moisture, 5–6% protein, 2.5%
crude fiber and 0.5–0.8 ash. The plant is culti-
vated for forage in India, Pakistan and the United
States (Texas).4.4.4.9.2 Structure,Properties.....................................
Guaran gum consists of a chain of β-D-
mannopyranosyl units joined by 1→4 linkages.
Every second residue has a side chain, aD-gal-
actopyranosyl residue that is bound to the
main chain by anα( 1 → 6 )linkage (cf. For-
mula 4.126).(4.144)Guaran gum forms highly viscous solutions (Ta-
ble 4.21), the viscosity of which is shear rate de-
pendent (Fig. 4.23).