8
Macroalgal Phycocolloids
Leonel Pereira
Introduction
Seaweeds have been utilized by mankind for several hundreds of years, directly for food, for medicinal
purposes, and for agriculture fertilizers. Today, seaweed is used in many countries for many different
purposes: directly as food, phycocolloids extraction, extraction of compounds with antiviral, antibacterial
or antitumor activity, and as biofertilizers (Rudolph 2000; Pereira 2010a,b).
About four million tonnes of seaweed are harvested annually worldwide. The major producers are
China and Japan, followed by America and Norway. France used to import Japanese seaweed in the
70s but ten years later, went on to produce algae for food and for biological products users. Unlike
what happens in East Asia, the West is more interested in thickeners and gelling properties of some
polysaccharides extracted from seaweeds. The use of seaweeds for fertilizer and soil improvement was
also well-known in Europe, and both large brown algae and calcified red algae have been collected for
this purpose (Guiry and Bluden 1991; Pereira 2010b).
Besides its vegetable nature, algae are sought due to the conjunction of variety of colors (and
shapes) and the blue ocean—a great selling point, both for food and cosmetics, especially after certain
substances of animal origin have become suspicious of transmitting the spongiform encephalopathy
(BSE), commonly known as mad-cow disease (Pereira 2004, 2010a,b).
The marine algae are a rich contributor to health—vitamins and trace elements, and also offer a wide
variety of flavors, fragrances, and textures. In fact, algae, as well as being a vitamin and mineral treasure,
are low in fat, an essential feature in weight loss diets. In addition, the algae are rich in dietary fiber, which
may facilitate intestinal transit, lower the rate of blood cholesterol, and reduce certain diseases such as
colon cancer (Pereira 2010a,b, 2011).
Phycocolloids
Phycocolloids refer to those polysaccharides extracted from both freshwater and marine algae. Until now,
only the polysaccharides extracted from marine red and brown algae, such as agar, carrageenan, and algin
are of economic and commercial significance, since these polysaccharides exhibit high molecular weights,
high viscosity, and excellent gelling, stabilizing and emulsifying features. They are also extracted in fairly
Department of Life Sciences, Faculty of Sciences and Technology, and MARE - Marine and Environmental Sciences Centre
University of Coimbra, Portugal.
Email: leonel.pereira@uc.pt, Webpage: www.uc.pt/seaweeds
Macroalgal Phycocolloids
Leonel Pereira
Introduction
Seaweeds have been utilized by mankind for several hundreds of years, directly for food, for medicinal
purposes, and for agriculture fertilizers. Today, seaweed is used in many countries for many different
purposes: directly as food, phycocolloids extraction, extraction of compounds with antiviral, antibacterial
or antitumor activity, and as biofertilizers (Rudolph 2000; Pereira 2010a,b).
About four million tonnes of seaweed are harvested annually worldwide. The major producers are
China and Japan, followed by America and Norway. France used to import Japanese seaweed in the
70s but ten years later, went on to produce algae for food and for biological products users. Unlike
what happens in East Asia, the West is more interested in thickeners and gelling properties of some
polysaccharides extracted from seaweeds. The use of seaweeds for fertilizer and soil improvement was
also well-known in Europe, and both large brown algae and calcified red algae have been collected for
this purpose (Guiry and Bluden 1991; Pereira 2010b).
Besides its vegetable nature, algae are sought due to the conjunction of variety of colors (and
shapes) and the blue ocean—a great selling point, both for food and cosmetics, especially after certain
substances of animal origin have become suspicious of transmitting the spongiform encephalopathy
(BSE), commonly known as mad-cow disease (Pereira 2004, 2010a,b).
The marine algae are a rich contributor to health—vitamins and trace elements, and also offer a wide
variety of flavors, fragrances, and textures. In fact, algae, as well as being a vitamin and mineral treasure,
are low in fat, an essential feature in weight loss diets. In addition, the algae are rich in dietary fiber, which
may facilitate intestinal transit, lower the rate of blood cholesterol, and reduce certain diseases such as
colon cancer (Pereira 2010a,b, 2011).
Phycocolloids
Phycocolloids refer to those polysaccharides extracted from both freshwater and marine algae. Until now,
only the polysaccharides extracted from marine red and brown algae, such as agar, carrageenan, and algin
are of economic and commercial significance, since these polysaccharides exhibit high molecular weights,
high viscosity, and excellent gelling, stabilizing and emulsifying features. They are also extracted in fairly
Department of Life Sciences, Faculty of Sciences and Technology, and MARE - Marine and Environmental Sciences Centre
University of Coimbra, Portugal.
Email: leonel.pereira@uc.pt, Webpage: www.uc.pt/seaweeds