Elemental Composition and Nutritional Potential of Wild Seaweeds from Northwest Africa: Implications for Agro-Food Applications

Abstract

Seaweed, like other living resources of the sea, can contribute to meeting the food and nutritional needs of African populations. Although food neophobia is likely, pressures from fish scarcity, climate change, and population growth make the inclusion of novel food from seaweeds increasingly necessary. The chemical content of various seaweeds in four locations over Senegal was determined, including minerals and heavy metals. A majority of the samples have cadmium concentrations exceeding the threshold for toxicity, and approximately half exceed the threshold for lead. We observed elevated levels of sodium (Na) and potassium (K) in Codium cylindricum, surpassing the nitrogen abundance. In one C. cylindricum sample, their concentrations were even higher than carbon, a rare occurrence in seaweeds. Some seaweed were highlighted for their significant contributions to key nutrients based on Codex Alimentarius's nutrient reference values: Caulerpa sp. for iron (77 – 84 %), C. cylindricum for potassium (15 %), Ulva sp. for magnesium (51 – 54 %), and Ellisolandia elongata for calcium (118 – 134 %). The Na/K ratios were below the WHO recommended ratio in C. cylindricum, Ulva sp., and E. elongata but exceeded it in Caulerpa sp.. Except for one Rhodophytae, all Chlorophytae in the Bryopsidales order exceeded the Na/K WHO recommendation. The presented insights, including review of half a century of phycological research in Senegal, provide a foundation for developing strategies to incorporate Senegalese seaweed into diets and agri-food products while supporting blue jobs and food in the framework of the blue economy in West Africa.

Keywords: Blue food, Codex alimentarius, Seaweed, Human diet, Codium cylindricum, Senegal