On average three hydroxyl groups are
available for derivatization per sugar unit in
guar gum. The maximum theoretical degree of
substitution (DS) in such molecule is three and
can be exceed three due to the additional
availability of hydroxyl groups.DS is defined
as average number of hydroxyl groups per
sugar unit. Primary hydroxyl group at C6
position is more susceptible to change but C2
and C3 positions are also good reacting sites.
Modification of GG is done by two ways either chemical modification or physical
modification to produced different derivatives
with variable degree of substitution.The
chemical amendments involves replacement of
free hydroxyl group of guar backbone by
different cationic, anionic, amphoteric and nonionic
groups. Physical alteration means
enzymatic, acidic and basic hydrolysis of guar
gum to yield low molecular weight gum.
Modification enhances properties and
applications of guar in broad spectrum of
industries. Several techniques may be applied
to obtain different derivatives of guar gum with
variable DS values.