Chemical Composition of Attached and Drift Specimens of Sargassum mangarevense and Turbinaria ornata (Phaeophyta: Fucales) from Tahiti, French Polynesia

The proximate composition, mineral and trace metal contents were determined for three different algal raw materials: attached Sargassum mangarevense , Turbinaria ornata and drift algae (almost entirely composed of these two species). Dietary fibre (38.1–42.8% dw) and ash (30.6–39.8% dw) were the most abundant constituents in all samples.A high protein content (13.2±1.9% dw) was found in S. mangarevense . All algae displayed similar amino acid patterns with a predominance of aspartic and glutamic acids (28.10–33.77% of total amino acids). Attached specimens had similar compositions of fatty acids, with a high concentration of polyunsaturated forms, especially C 18 and C 20 . All samples showed a high mineral content, particularly in calcium, magnesium, potassium ( T. ornata ), iodine ( S. mangarevense ), iron and zinc. The drift algae usually accumulated more minerals than the attached algae. The potential use of both attached and drift algae as fertilisers, animal food and cosmetic products is discussed.