152 Marine Macro- and Microalgae: An Overview
Carrageenans are the third most important hydrocolloid in the food industry, after gelatin (animal
origin) and starch (plant origin) (van de Velde and de Ruiter 2002). The most commonly used, commercial
carrageenans are extracted from Kappaphycus alvarezii and Eucheuma denticulatum (McHugh 2003).
Primarily, wild-harvested genera such as Chondrus, Furcellaria, Gigartina, Chondracanthus,
Sarcothalia, Mazzaella, Iridaea, Mastocarpus, and Tichocarpus are also mainly cultivated as carrageenan
raw materials and producing countries include Argentina, Canada, Chile, Denmark, France, Japan,
Mexico, Morocco, Portugal, North Korea, South Korea, Spain, Russia, and USA (Pereira et al. 2009c;
Bixler and Porse 2011).
The original source of carrageenans was from the red seaweed Chondrus crispus, which continues to
be used but in limited quantities. Betaphycus gelatinum is used for the extraction of beta (β) carrageenan.
Some South American red algae (used previously only in minor quantities) have been receiving attention
from carrageenan producers, as they seek to increase diversification of raw materials in order to provide
for the extraction of new carrageenan types with different physical functionalities, and therefore promote
product development, which in turn stimulates demand (McHugh 2003). Gigartina skottsbergii, Sarcothalia
crispata, and Mazzaella laminaroides are currently the most valuable species, and all are harvested from
natural populations in Chile and Peru. The recent earthquake in Chile (27 February 2010), which caused
the elevation of intertidal areas and the consequent large losses of harvestable biomass (Pereira 2011)
should be mentioned in this regard. Small quantities of Gigartina canaliculata are harvested in Mexico
and Hypnea musciformis has been used in Brazil (Furtado 1999). The use of high value carrageenophytes
as a dissolved organic nutrient sink to boost economic viability of integrated multitrophic aquaculture
(IMTA) operations has also been considered (Pereira 2004; Chopin 2006; Sousa-Pinto and Abreu 2011).
Large carrageenan processors have fuelled development of Kappaphycus alvarezii (which goes by
the name “cottonii” to the trade) and Eucheuma denticulatum (commonly referred to as “spinosum”)
farming in several countries including Philippines, Indonesia, Malaysia, Tanzania, Kiribati, Fiji, Kenya,
and Madagascar (McHugh 2003). Indonesia has recently overtaken the Philippines as the world’s largest
producer of dried carrageenophytes biomass (Pereira 2011).
Shortages of carrageenan-producing seaweeds suddenly appeared in mid-2007, resulting in doubling
of its price; some of this price increase was due to increased fuel costs and a weak US dollar (most seaweed
polysaccharides are traded in US dollars). The reasons for shortages of the raw materials for processing
are less certain: perhaps it is a combination of environmental factors, sudden increases in demand,
particularly from China, and some market manipulation by farmers and traders. Most hydrocolloids are
indeed experiencing severe price changes.
However, the monocultures of some carrageenophytes (namely Kappaphycus alvarezii) have several
problems due to environmental change and also diseases. The problems with ice-ice and epiphytes have
resulted in large scale crop losses (Vairappan et al. 2008; Hayashi et al. 2010; Hurtado et al. 2016).
Uronates
Alginates. “Alginate” is the term usually used for the salts of alginic acid, but it can also refer to all the
derivatives of alginic acid and alginic acid itself; in some publications, the term “algin” is used instead
of alginate. Alginate is a linear copolymer of β-D-mannuronic acid (M) and α-L-guluronic acid (G)
(1→4)-linked residues, arranged either in heteropolymeric (MG) and/or homopolymeric (M or G) blocks
(Larsen et al. 2003; Pereira et al. 2003; Leal et al. 2008).
Alginic acid was discovered in 1883 by Stanford, a British pharmacist who called it “algin”. In
seaweeds, algin is extracted as a mixed salt of sodium and/or potassium, calcium, and magnesium. The
exact composition varies with algal species. Since its discovery, the name has been applied to a number of
substances, for example, alginic acid and all alginates, derived from alginic acid. The extraction process
is based on the conversion of an insoluble mixture of alginic acid salts of the cell wall in a soluble salt
(alginate), which is appropriate for the water extraction (Lobban et al. 1988; Lahaye 2001).
Alginic acid is present in the cell walls of brown seaweeds, and it is partly responsible for the
flexibility of the seaweed. Consequently, brown seaweeds that grow in more turbulent conditions usually
have higher alginate content than those in calmer waters. While any brown seaweed could be used as
Carrageenans are the third most important hydrocolloid in the food industry, after gelatin (animal
origin) and starch (plant origin) (van de Velde and de Ruiter 2002). The most commonly used, commercial
carrageenans are extracted from Kappaphycus alvarezii and Eucheuma denticulatum (McHugh 2003).
Primarily, wild-harvested genera such as Chondrus, Furcellaria, Gigartina, Chondracanthus,
Sarcothalia, Mazzaella, Iridaea, Mastocarpus, and Tichocarpus are also mainly cultivated as carrageenan
raw materials and producing countries include Argentina, Canada, Chile, Denmark, France, Japan,
Mexico, Morocco, Portugal, North Korea, South Korea, Spain, Russia, and USA (Pereira et al. 2009c;
Bixler and Porse 2011).
The original source of carrageenans was from the red seaweed Chondrus crispus, which continues to
be used but in limited quantities. Betaphycus gelatinum is used for the extraction of beta (β) carrageenan.
Some South American red algae (used previously only in minor quantities) have been receiving attention
from carrageenan producers, as they seek to increase diversification of raw materials in order to provide
for the extraction of new carrageenan types with different physical functionalities, and therefore promote
product development, which in turn stimulates demand (McHugh 2003). Gigartina skottsbergii, Sarcothalia
crispata, and Mazzaella laminaroides are currently the most valuable species, and all are harvested from
natural populations in Chile and Peru. The recent earthquake in Chile (27 February 2010), which caused
the elevation of intertidal areas and the consequent large losses of harvestable biomass (Pereira 2011)
should be mentioned in this regard. Small quantities of Gigartina canaliculata are harvested in Mexico
and Hypnea musciformis has been used in Brazil (Furtado 1999). The use of high value carrageenophytes
as a dissolved organic nutrient sink to boost economic viability of integrated multitrophic aquaculture
(IMTA) operations has also been considered (Pereira 2004; Chopin 2006; Sousa-Pinto and Abreu 2011).
Large carrageenan processors have fuelled development of Kappaphycus alvarezii (which goes by
the name “cottonii” to the trade) and Eucheuma denticulatum (commonly referred to as “spinosum”)
farming in several countries including Philippines, Indonesia, Malaysia, Tanzania, Kiribati, Fiji, Kenya,
and Madagascar (McHugh 2003). Indonesia has recently overtaken the Philippines as the world’s largest
producer of dried carrageenophytes biomass (Pereira 2011).
Shortages of carrageenan-producing seaweeds suddenly appeared in mid-2007, resulting in doubling
of its price; some of this price increase was due to increased fuel costs and a weak US dollar (most seaweed
polysaccharides are traded in US dollars). The reasons for shortages of the raw materials for processing
are less certain: perhaps it is a combination of environmental factors, sudden increases in demand,
particularly from China, and some market manipulation by farmers and traders. Most hydrocolloids are
indeed experiencing severe price changes.
However, the monocultures of some carrageenophytes (namely Kappaphycus alvarezii) have several
problems due to environmental change and also diseases. The problems with ice-ice and epiphytes have
resulted in large scale crop losses (Vairappan et al. 2008; Hayashi et al. 2010; Hurtado et al. 2016).
Uronates
Alginates. “Alginate” is the term usually used for the salts of alginic acid, but it can also refer to all the
derivatives of alginic acid and alginic acid itself; in some publications, the term “algin” is used instead
of alginate. Alginate is a linear copolymer of β-D-mannuronic acid (M) and α-L-guluronic acid (G)
(1→4)-linked residues, arranged either in heteropolymeric (MG) and/or homopolymeric (M or G) blocks
(Larsen et al. 2003; Pereira et al. 2003; Leal et al. 2008).
Alginic acid was discovered in 1883 by Stanford, a British pharmacist who called it “algin”. In
seaweeds, algin is extracted as a mixed salt of sodium and/or potassium, calcium, and magnesium. The
exact composition varies with algal species. Since its discovery, the name has been applied to a number of
substances, for example, alginic acid and all alginates, derived from alginic acid. The extraction process
is based on the conversion of an insoluble mixture of alginic acid salts of the cell wall in a soluble salt
(alginate), which is appropriate for the water extraction (Lobban et al. 1988; Lahaye 2001).
Alginic acid is present in the cell walls of brown seaweeds, and it is partly responsible for the
flexibility of the seaweed. Consequently, brown seaweeds that grow in more turbulent conditions usually
have higher alginate content than those in calmer waters. While any brown seaweed could be used as