title: Chemical composition of selected seaweeds from the Indian Ocean, KwaZulu-Natal coast, South Africa.
abstract: The chemical composition of three edible seaweeds (Codium capitatum, Hypnea spicifera and Sargassum elegans) and two inedible seaweeds (Halimeda cuneata and Spyridia hypnoides) from the Indian Ocean along the KwaZulu-Natal East Coast, South Africa were investigated as a function of seasonal variation. The proximate compositions of the edible seaweeds were determined. In edible seaweeds, the moisture level ranged from 85.4 to 89.5%, protein from 6.1 to 11.8%, lipids from 7.5 to 13.1% and carbohydrates from 37.8 to 71.9%. Elemental concentrations in the five studied seaweeds varied significantly with season (P < 0.05) with mean elemental concentrations (in µg g(-1), dry weight) being: Ca (29 260), Mg (6 279), Fe (1 086), Cu (145.9), Mn (48.32), As (24.29), Zn (15.65), Ni (9.83), Cr (5.78), Pb (4.84), Co (0.87) and Se (0.86). The concentrations of As were particularly high in S. elegans, ranging from 94.70 ± 6.6 µg g(-1) in winter to 65.10 ± 2.3 µg g(-1) in summer. Hierarchical cluster analysis showed similar distribution of elements in edible seaweeds which was dissimilar to that in inedible seaweeds. This study suggests that edible macro alga, C. capitatum and H. spicifera, could be potential sources of most essential nutrients and may contribute positively to the diet without posing the risk of adverse health effects due to low concentrations of toxic elements. However, due to high levels of As in S. elegans, its consumption should be moderated to reduce dietary exposure to this toxic element.
authors.affiliation: a School of Chemistry and Physics, University of KwaZulu-Natal , Durban , South Africa.
authors.forename: Judie
authors.initials: J
authors.lastname: Magura
authors.affiliation: a School of Chemistry and Physics, University of KwaZulu-Natal , Durban , South Africa.
authors.forename: Roshila
authors.initials: R
authors.lastname: Moodley
authors.affiliation: a School of Chemistry and Physics, University of KwaZulu-Natal , Durban , South Africa.
authors.forename: Sreekantha B
authors.initials: SB
authors.lastname: Jonnalagadda
mesh_terms: D000460:Chlorophyta / Q000737:chemistry*; D019156:Indian Ocean; D010945:Plants, Edible / Q000737:chemistry*; D012621:Seasons; D012624:Seaweed / Q000737:chemistry*; D013019:South Africa; D014131:Trace Elements / Q000032:analysis*
chemical_list: D014131:Trace Elements
keywords: Arsenic; edible seaweeds; marine macro algae; seasonal variation; trace elements; zinc