Study of the chemical composition of edible red macroalgae Grateloupia turuturu from Brittany (France)

The chemical composition and its seasonal variation of the red seaweed Grateloupia turuturu, an invasive macroalgae from Brittany, France, were investigated. Size, ash, protein, lipid, dietary fibre (soluble, insoluble and total), protein pigment (R-phycoerythrin, R-phycocyanin), and fatty acid content were measured in G. turuturu samples collected over 1 year (2006). The average size of this seaweed was 32.0 cm long and approximately 5.0 cm wide, while the size of the thallus was maximal in June (in length and width). On the dry weight basis, this alga was constituted of more than 18% ash, about 23% protein, 2.6% lipids, and approximately 60% dietary fibre. The most abundant fatty acids were palmitic acid and eicosapentaenoic acid (52% and 12% of the fatty acid fraction, respectively). The study of seasonal variations showed that the best period to collect the seaweed for food use is between February and June.