Chapter 6
Carrageenans
Abstract Carrageenans are the sulfated polysaccharides that are obtained from red
algae. They are most commonly applied as gelling agents. They are made up of
alternating disaccharide units of 1, 3 linked beta galactose linked to either 1,4 alpha
galactopyranose or 3,6 anhydrogalactose. They are classified as either λ, κ, ι, ε, μ,
depending on the degree of sulfation. The extraction process makes use of alkali,
acids and salts and requires energy for heating and additional processes to recover
and purify carrageenan from seaweed biomass. These are considered in evaluating
the environmental impact of carrageenan production. Presently, carrageenan is more
commonly used for its rheological properties as a gelling agent in food and other
consumer goods. Some studies have also presented potential application as a bioactive
compound and in renewable energy system components.
Keywords Carrageenan · Polymer · Polysaccharide · Phycocolloids · Algae
6.1 Introduction
Red algae are a source of polysaccharides. The polysaccharides serve as structural
as well as functional compounds within the red algae cell wall. Carrageenans are the
sulfated polysaccharides present in the cell walls of red algae where they play mainly
structural roles. They are one of the aquatic sourced polymers which are exclusive to
the aquatic ecosystem. The only known source of carrageenan is the red algae which
grow mainly in the epipelagic zones of the sea, and more rarely some species grow
in littoral zones of freshwater with moderate flow rate (Sheath and Vis 2015). The
harvesting of feedstock for carrageenan production is therefore from within these
regions of the aquatic ecosystem or simulation of these environments in aquaculture
for the cultivation of the feedstock.
Familiar consumer products within which carrageenans are commonly applied
include toothpastes, air fresheners and pet food. The important role carrageenan
plays in these fast moving consumer goods puts it at a value of around 300 million
USD (McHugh 2003). The value of the aquatic environment is extended to not only
the market value of the resources directly obtained from it but also the products
obtainable from these resources. While the present commercial value of carrageenan
© Springer International Publishing 2020
O. Olatunji, Aquatic Biopolymers, Springer Series on Polymer and Composite Materials,
https://doi.org/10.1007/978-3-030-34709-3_6
121
Carrageenans
Abstract Carrageenans are the sulfated polysaccharides that are obtained from red
algae. They are most commonly applied as gelling agents. They are made up of
alternating disaccharide units of 1, 3 linked beta galactose linked to either 1,4 alpha
galactopyranose or 3,6 anhydrogalactose. They are classified as either λ, κ, ι, ε, μ,
depending on the degree of sulfation. The extraction process makes use of alkali,
acids and salts and requires energy for heating and additional processes to recover
and purify carrageenan from seaweed biomass. These are considered in evaluating
the environmental impact of carrageenan production. Presently, carrageenan is more
commonly used for its rheological properties as a gelling agent in food and other
consumer goods. Some studies have also presented potential application as a bioactive
compound and in renewable energy system components.
Keywords Carrageenan · Polymer · Polysaccharide · Phycocolloids · Algae
6.1 Introduction
Red algae are a source of polysaccharides. The polysaccharides serve as structural
as well as functional compounds within the red algae cell wall. Carrageenans are the
sulfated polysaccharides present in the cell walls of red algae where they play mainly
structural roles. They are one of the aquatic sourced polymers which are exclusive to
the aquatic ecosystem. The only known source of carrageenan is the red algae which
grow mainly in the epipelagic zones of the sea, and more rarely some species grow
in littoral zones of freshwater with moderate flow rate (Sheath and Vis 2015). The
harvesting of feedstock for carrageenan production is therefore from within these
regions of the aquatic ecosystem or simulation of these environments in aquaculture
for the cultivation of the feedstock.
Familiar consumer products within which carrageenans are commonly applied
include toothpastes, air fresheners and pet food. The important role carrageenan
plays in these fast moving consumer goods puts it at a value of around 300 million
USD (McHugh 2003). The value of the aquatic environment is extended to not only
the market value of the resources directly obtained from it but also the products
obtainable from these resources. While the present commercial value of carrageenan
© Springer International Publishing 2020
O. Olatunji, Aquatic Biopolymers, Springer Series on Polymer and Composite Materials,
https://doi.org/10.1007/978-3-030-34709-3_6
121