Macroalgal Phycocolloids 149
II by H.H. Selby and C.K. Tseng. This work was supported by the American Government that wanted
the country to be self-sufficient in strategic needs, especially with regard to bacteriological culture media
(Armisen and Galatas 2000).
Apart from the above American production, practically the only producer of this phycocolloid
until World War II was the Japanese industry, which held a very traditional industrial structure based on
numerous small factories (about 400 factories operated simultaneously). These factories were familyoperated, producing a non-standardized quality, and had a high employment rate as production was not
mechanized. For this reason, and in spite of the later installation of some factories of a medium to small
size, only in recent times has Japan operated modern industrial plants especially for the agar plants
(McHugh 2003).
During the Second World War, the shortage of available agar acted as an incentive for those countries
with coastal resources of Gelidum corneum (formerly Gelidium sesquipedale), which is very similar
to the Gelidium pacificum used by the Japanese industry. Hence, Loureiro started the agar industry in
Oporto (Portugal), while at the same time J. Mejias and F. Cabrero, in Spain, commenced studies that
led to establishment of the important Iberian agar industry. Other European countries that did not have
agarophytes tried to prepare agar substitutes from other seaweed extracts (Minghou 1990; Sousa-Pinto
1998; McHugh 2003; Pereira 2008).
Agar is a phycocolloid named by Malaysians that means “red alga” in general, and has traditionally
been applied to what we now know taxonomically as—Eucheuma. Ironically, we now know this to
be the commercial source of iota carrageenan. Agar is composed of two polysaccharides: agarose and
agaropectin. The first is responsible for gelling, while the latter has thickening properties (Armisen and
Galatas 2000; Pereira 2011).
Most agar is extracted from species of Gelidium and Gracilaria. Closely related to Gelidium are species
of Pterocladiella, and small quantities of these are collected mainly in Azores (Portugal) and New Zealand.
Gelidiella acerosa is the main source of agar in India. Ahnfeltia species have been used in both Russia and
Japan, one source being the island of Sakhalin (Russia) (Cardoso et al. 2014) Gelidium spp. and Gracilaria
spp. are collected in Portugal, Morocco, Tunisia, and Chile for agar production (Mouradi-Givernaud et al.
1999; Givernaud et al. 2005; Givernaud and Mouradi 2006; Krisler 2006; Ortiz et al. 2009).
Agar is a relatively mature industry in terms of manufacturing methods and applications. Nowadays,
most processors are using press/syneresis technology; although some still favor freeze/thaw technology
or a mixture of these technologies. While the basic processes may not have changed, improvements in
presses and freezing equipment should be noted. High-pressure membrane presses have greatly improved
dewatering of agar, and thereby reduced energy requirements for final drying before powder milling.
The origin of agar as a food ingredient lies in Asia, where it has been consumed for several centuries.
Its extraordinary qualities as a thickening, stabilizing, and gelling agent make it an essential ingredient for
preparing processed food products. Furthermore, its satiating and gut regulating characteristics make it an
ideal fiber ingredient in the preparation of low calorie food products. The principal applications of agar
food grade are (see Table 2): fruit jellies, milk products, fruit pastilles, caramels, chewing gum, canned
meat, soups, confectionery and baked goods, icing, and frozen and salted fish (Armisen and Galatas
2000).
…Table 1 contd.
Industrial and Lab Uses
Paints
Alginate
Provide viscosity, glazing
Textiles
Agar, Carrageenan
Provide sizing and glazing
Paper making
Alginate, Agar, Carrageenan Provide viscosity and thickening
Analytical separation
Alginate, Carrageenan
Gel
Bacteriological media
Agar
Gel
Electrophoresis gel
Agar, Carrageenan
Gel
Non-seaweed colloids: CF – Carob flour; GG – Guar gum; X – Xanthan.
Use
Phycocolloid
Function
II by H.H. Selby and C.K. Tseng. This work was supported by the American Government that wanted
the country to be self-sufficient in strategic needs, especially with regard to bacteriological culture media
(Armisen and Galatas 2000).
Apart from the above American production, practically the only producer of this phycocolloid
until World War II was the Japanese industry, which held a very traditional industrial structure based on
numerous small factories (about 400 factories operated simultaneously). These factories were familyoperated, producing a non-standardized quality, and had a high employment rate as production was not
mechanized. For this reason, and in spite of the later installation of some factories of a medium to small
size, only in recent times has Japan operated modern industrial plants especially for the agar plants
(McHugh 2003).
During the Second World War, the shortage of available agar acted as an incentive for those countries
with coastal resources of Gelidum corneum (formerly Gelidium sesquipedale), which is very similar
to the Gelidium pacificum used by the Japanese industry. Hence, Loureiro started the agar industry in
Oporto (Portugal), while at the same time J. Mejias and F. Cabrero, in Spain, commenced studies that
led to establishment of the important Iberian agar industry. Other European countries that did not have
agarophytes tried to prepare agar substitutes from other seaweed extracts (Minghou 1990; Sousa-Pinto
1998; McHugh 2003; Pereira 2008).
Agar is a phycocolloid named by Malaysians that means “red alga” in general, and has traditionally
been applied to what we now know taxonomically as—Eucheuma. Ironically, we now know this to
be the commercial source of iota carrageenan. Agar is composed of two polysaccharides: agarose and
agaropectin. The first is responsible for gelling, while the latter has thickening properties (Armisen and
Galatas 2000; Pereira 2011).
Most agar is extracted from species of Gelidium and Gracilaria. Closely related to Gelidium are species
of Pterocladiella, and small quantities of these are collected mainly in Azores (Portugal) and New Zealand.
Gelidiella acerosa is the main source of agar in India. Ahnfeltia species have been used in both Russia and
Japan, one source being the island of Sakhalin (Russia) (Cardoso et al. 2014) Gelidium spp. and Gracilaria
spp. are collected in Portugal, Morocco, Tunisia, and Chile for agar production (Mouradi-Givernaud et al.
1999; Givernaud et al. 2005; Givernaud and Mouradi 2006; Krisler 2006; Ortiz et al. 2009).
Agar is a relatively mature industry in terms of manufacturing methods and applications. Nowadays,
most processors are using press/syneresis technology; although some still favor freeze/thaw technology
or a mixture of these technologies. While the basic processes may not have changed, improvements in
presses and freezing equipment should be noted. High-pressure membrane presses have greatly improved
dewatering of agar, and thereby reduced energy requirements for final drying before powder milling.
The origin of agar as a food ingredient lies in Asia, where it has been consumed for several centuries.
Its extraordinary qualities as a thickening, stabilizing, and gelling agent make it an essential ingredient for
preparing processed food products. Furthermore, its satiating and gut regulating characteristics make it an
ideal fiber ingredient in the preparation of low calorie food products. The principal applications of agar
food grade are (see Table 2): fruit jellies, milk products, fruit pastilles, caramels, chewing gum, canned
meat, soups, confectionery and baked goods, icing, and frozen and salted fish (Armisen and Galatas
2000).
…Table 1 contd.
Industrial and Lab Uses
Paints
Alginate
Provide viscosity, glazing
Textiles
Agar, Carrageenan
Provide sizing and glazing
Paper making
Alginate, Agar, Carrageenan Provide viscosity and thickening
Analytical separation
Alginate, Carrageenan
Gel
Bacteriological media
Agar
Gel
Electrophoresis gel
Agar, Carrageenan
Gel
Non-seaweed colloids: CF – Carob flour; GG – Guar gum; X – Xanthan.
Use
Phycocolloid
Function