The algae of the Portuguese coast are of great nutritional value
José Pichel Andrés/DICYT The Centre for Environmental and Marine Studies (Centro de Estudos do Ambiente e do Mar, CESAM) of the University of Aveiro, in collaboration with the Universidade Católica Portuguesa of Oporto, has studied the chemical composition of several species of edible seaweed from the west coast of Portugal to reveal their high nutritional value. The results of this research may help to develop new functional foods containing specific compounds for improving health or reducing the risk of contracting diseases.
“Seaweed is part of the diet of many people in various parts of the world and is also becoming more important as food in western countries, where interest in it is growing and it is becoming more accepted owing to its nutritional qualities and the possibility of using it to prevent and combat disease”, DiCYT was told by Dina Rodrigues, a researcher of the CESAM and one of the directors of this study which has been published in the scientific journal Food Chemistry.
In general algae are low in calories and very rich in proteins, minerals, vitamins, and molecules known as polysaccharides, which are biological anticoagulants and help to prevent cancer among other properties. Moreover, “they represent an alternative source of protein and are cheaper than those of animal origin”, the scientist points out. Potentially therefore they have a high added value as an economic resource, for instance if algae extracts are used as functional ingredients.
However, there are so many different species that scientists have a lot of work to do if they are to get to know this marine resource better. This study concentrated on six species: Osmundea pinnatifida, Grateloupia turuturu, Gracilaria gracilis, Sargassum muticum, Saccorhiza polyschides, and Codium tomentosum. All of them were gathered in the Buarcos bay in Figueira da Foz. This enclave has been chosen for its geographical position. “Buarcos has both northern and southern influences; it is a transition area with algae of various origins, including typical species from the north Atlantic of cool temperate waters and others from North Africa and the Mediterranean of warm temperate waters”, Dina Rodrigues comments.
The tern macroalgae is used to distinguish multicellular algae from microscopic algae and they are classified in three different groups according to their pigmentation: Phaeophyceae (brown), Rhodophyceae (red), and Chlorophyceae (green). The chemical composition of each group is different, but it also varies according to the species, the geographical location, the time of the year, or the environmental conditions. This study has allowed the observation of considerable differences in the content of proteins, sugars, and fats and the confirmation that some polysaccharides are specific to certain species.
On the other hand, the species Sargassum muticum and Saccorhiza polyschides stand out for their content in two types of polysaccharides, alginates, and fucoidans, while Grateloupia turuturu, Gracilaria gracilis and Osmundea pinnatifida are a major source of another two, carrageenan and agar. Although all algae analysed were already considered to be edible prior to this study, few data existed on their composition, in particular in the case of Osmundea pinnatifida. The high iron content found in Gracilaria gracilis, Grateloupia turuturu, and Sacchorhiza polyschides and the high magnesium content in Sargassum muticum is noteworthy.
“The main aim of our research work is the development of new functional foods by means of the incorporation of extracts or compounds associated with specific properties”, the researcher declares. For this reason her group intends to carry out further studies on the biological activities of the components of algae and their possible inclusion in food. “There is no doubt that macroalgae constitute a huge source of new functional ingredients that are considered beneficial to health; we can and should exploit them”, she adds.
Chemical composition of red, brown and green macroalgae from Buarcos bay in Central West Coast of Portugal. Dina Rodrigues, Ana C. Freitas, Leonel Pereira, Teresa A.P. Rocha-Santos, Marta W. Vasconcelos, Mariana Roriz, Luís M. Rodríguez-Alcalá, Ana M.P. Gomes, Armando C. Duarte. Food Chemistry, Volume 183, 15 September 2015, Pages 197–207. doi:10.1016/j.foodchem.2015.03.057