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Microbial Gums
Carrageenan Gum
Carrageenan is the generic name for high molecular weight sulphated polysaccharide of D-galactose and 3,6-anhydro-D-galactose or a linear structure consisting of
D-galactose units alternatively linked by α- (1–3) and α- (1–4) bonds and isolated
from red weeds belonging to the class Rhodophyceae, especially Chondruscrispus,
Euchema spp, Gigartinastellata and Iridaea spp. The polymer chains comprise
alternating (1 → 3)-linked β-d-galactopyranosyl and (1 → 4)-linked α-dgalactopyranosyl units. Some of the (1 → 3) linked units occur as the 2- and
4- sulfates, whereas the (1 → 4) linked units occur as the 2- and 6- sulfates, the
2,6-disulfates, the 3,6-anhydride, and the 3,6-andydride-2-sulfate. Carrageenan has
been broadly divided into three types based on difference in the number of sulphate
groups (kappa (κ), iota (ι) and lambda (λ)). Carrageenan safety in terms of use in
food systems has been approved jointly by FAO/WHO. Carrageenan and its derivatives have been used in various pharmaceutical formulations for use as a mucoadhesive material e.g. pravastatin was encapsulated using carrageenan as a wall
material.
Alginate Gum
Modification of Dietary Gums
This nontoxic, linear heteropolysaccharide consists of anionic copolymer comprising of 1 → 4 linked β-D-mannuronic acid (M residue) and α-L-guluronic acids (G
residue), obtained from brown sea algae and some bacterias. The versatility and
positive cellular response of this unbranched binary copolymer polysaccharide
makes it a promising candidate for the development of hydrogel particles and scaffolds. It exists in three forms as homopolymeric M-blocks (M-M-M). Ion binding
sites in alginates are controlled by the cavities formed by diaxially linked G residues
proving junction zone in the gel network. This binding zone between the G-block is
described as the egg-box model. Therefore, the length of D-manuronic acid polymer
is a major structure contributing factor to gel formation and subsequent instantaneous entrapment of probiotic cells in three-dimensional lattice of alginates. Other
factors known to affect gel formation of alginates includes concentration of the
alginate and CaCl 2 and gel hardening time. These anionic copolymer vary widely in
composition and sequence and are arranged in a pattern of blocks along the chain.
The average molecular weight of alginate is in the range of 200,000–300,000 Da
however, molecular weight and polymerization degree depends on the enzymatic
activity at the time of extraction/production, isolation process and biotechnological
procedure. The average weight of the alginate is in the range 4 × 10
4
–5 × 10
5
g/mol.
Dietary Gums
Microbial Gums
Carrageenan Gum
Carrageenan is the generic name for high molecular weight sulphated polysaccharide of D-galactose and 3,6-anhydro-D-galactose or a linear structure consisting of
D-galactose units alternatively linked by α- (1–3) and α- (1–4) bonds and isolated
from red weeds belonging to the class Rhodophyceae, especially Chondruscrispus,
Euchema spp, Gigartinastellata and Iridaea spp. The polymer chains comprise
alternating (1 → 3)-linked β-d-galactopyranosyl and (1 → 4)-linked α-dgalactopyranosyl units. Some of the (1 → 3) linked units occur as the 2- and
4- sulfates, whereas the (1 → 4) linked units occur as the 2- and 6- sulfates, the
2,6-disulfates, the 3,6-anhydride, and the 3,6-andydride-2-sulfate. Carrageenan has
been broadly divided into three types based on difference in the number of sulphate
groups (kappa (κ), iota (ι) and lambda (λ)). Carrageenan safety in terms of use in
food systems has been approved jointly by FAO/WHO. Carrageenan and its derivatives have been used in various pharmaceutical formulations for use as a mucoadhesive material e.g. pravastatin was encapsulated using carrageenan as a wall
material.
Alginate Gum
Modification of Dietary Gums
This nontoxic, linear heteropolysaccharide consists of anionic copolymer comprising of 1 → 4 linked β-D-mannuronic acid (M residue) and α-L-guluronic acids (G
residue), obtained from brown sea algae and some bacterias. The versatility and
positive cellular response of this unbranched binary copolymer polysaccharide
makes it a promising candidate for the development of hydrogel particles and scaffolds. It exists in three forms as homopolymeric M-blocks (M-M-M). Ion binding
sites in alginates are controlled by the cavities formed by diaxially linked G residues
proving junction zone in the gel network. This binding zone between the G-block is
described as the egg-box model. Therefore, the length of D-manuronic acid polymer
is a major structure contributing factor to gel formation and subsequent instantaneous entrapment of probiotic cells in three-dimensional lattice of alginates. Other
factors known to affect gel formation of alginates includes concentration of the
alginate and CaCl 2 and gel hardening time. These anionic copolymer vary widely in
composition and sequence and are arranged in a pattern of blocks along the chain.
The average molecular weight of alginate is in the range of 200,000–300,000 Da
however, molecular weight and polymerization degree depends on the enzymatic
activity at the time of extraction/production, isolation process and biotechnological
procedure. The average weight of the alginate is in the range 4 × 10
4
–5 × 10
5
g/mol.
Dietary Gums