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Guar Gum
Guar gum is a galactomannan also known as locust bean gum, tara gum, carob bean
gum. It is a nonionic, biodegradable, water-soluble, and low-cost natural polysaccharide obtained from seeds of Cyamopsis tetragonoloba (Carob tree). It is composed of linear chains of 1 attached β-d-(1 → 4) mannopyranosyl unit and short-side
branched alfa-D-galactopyranosyl units attached at (1–6) linkages. Locust bean
gum is one of the most widely used gums for controlled and targeted delivery in
colon and is used in medicinal industry as a binder, disintegrator, hydrophilic
matrix and an encapsulating agent. Guar gum is soluble in cold water and remains
stable in the pH range of 5–7, but forms a gel like structure in hot water. The solution of this gum exhibits pseudo plastic behavior, and finds use as a thickener,
emulsifier and retarding agent in food industry. Guar gum has been used as an
encapsulating agent in various formulations as it remains unaffected in the upper
digestive tract but gets easily degraded by microflora in the colon. The highly viscous nature of guar gum limits its use in encapsulation and hence various modifications can be employed including physical, chemical, enzymatic or a combination of
hydrocolloids to increase its functionality. Guar gum can be modified by derivatization, grafting, network formation and by the use of acids, enzymes, hydrothermal
degradation, microwave mediated free radical degradation, and irradiation in particular ultrasonication to improve its properties for diverse biomedical applications.
Guar gum nanoparticles have been prepared by nano-precipitation and crosslinking
methods. Different factors responsible for the nanoparticle formation are the
molecular mass of the galactomannan, solvent surfactant, crosslinking and
agitation.
Gum Karaya
Gum karaya also known as Sterculia gum is a complex polysaccharide obtained as
a calcium and magnesium salt with a molecular mass of up to 1.6 × 10
7
g/mol. It is
obtained from the stems and branches of Sterculia urens Roxb and other species of
it or from the species of Cochlospermum. It is mainly grown in the Asian continent,
particularly in India. The backbone of the karaya gum consists of α-d-galacturonic
acid, α-l-rhamnose residues and side chains are attached by (1 → 2) or (1 → 3) linkage of β-d-galactose to the main chain. The color of this gum is white to grayish
white and has a 10% solubility in room temperature water and 30% soluble in
hot water.
P. Chatur et al.
Guar Gum
Guar gum is a galactomannan also known as locust bean gum, tara gum, carob bean
gum. It is a nonionic, biodegradable, water-soluble, and low-cost natural polysaccharide obtained from seeds of Cyamopsis tetragonoloba (Carob tree). It is composed of linear chains of 1 attached β-d-(1 → 4) mannopyranosyl unit and short-side
branched alfa-D-galactopyranosyl units attached at (1–6) linkages. Locust bean
gum is one of the most widely used gums for controlled and targeted delivery in
colon and is used in medicinal industry as a binder, disintegrator, hydrophilic
matrix and an encapsulating agent. Guar gum is soluble in cold water and remains
stable in the pH range of 5–7, but forms a gel like structure in hot water. The solution of this gum exhibits pseudo plastic behavior, and finds use as a thickener,
emulsifier and retarding agent in food industry. Guar gum has been used as an
encapsulating agent in various formulations as it remains unaffected in the upper
digestive tract but gets easily degraded by microflora in the colon. The highly viscous nature of guar gum limits its use in encapsulation and hence various modifications can be employed including physical, chemical, enzymatic or a combination of
hydrocolloids to increase its functionality. Guar gum can be modified by derivatization, grafting, network formation and by the use of acids, enzymes, hydrothermal
degradation, microwave mediated free radical degradation, and irradiation in particular ultrasonication to improve its properties for diverse biomedical applications.
Guar gum nanoparticles have been prepared by nano-precipitation and crosslinking
methods. Different factors responsible for the nanoparticle formation are the
molecular mass of the galactomannan, solvent surfactant, crosslinking and
agitation.
Gum Karaya
Gum karaya also known as Sterculia gum is a complex polysaccharide obtained as
a calcium and magnesium salt with a molecular mass of up to 1.6 × 10
7
g/mol. It is
obtained from the stems and branches of Sterculia urens Roxb and other species of
it or from the species of Cochlospermum. It is mainly grown in the Asian continent,
particularly in India. The backbone of the karaya gum consists of α-d-galacturonic
acid, α-l-rhamnose residues and side chains are attached by (1 → 2) or (1 → 3) linkage of β-d-galactose to the main chain. The color of this gum is white to grayish
white and has a 10% solubility in room temperature water and 30% soluble in
hot water.
P. Chatur et al.