Unlocking the potential of cultivated seaweeds Ecklonia radiata and Cladophora sp. for sustainable future foods: nutritional value, fatty acid profile, and microbial safety

Abstract

Marine macroalgae are increasingly recognized as valuable resources to develop sustainable functional foods due to their diverse biochemical compositions. Their cultivation has become an important sector in global aquaculture that aims to provide sustainable sources of biomass and expand their potential applications. However, biomass obtained from many emerging farming operations requires thorough evaluation of its nutritional profile. This study evaluated the nutritional composition of Ecklonia radiata and Cladophora sp. cultivated in Australian farms and their potential use in future food applications. To ensure the traceability and consistency of raw materials, analyses were conducted on total carbohydrate and protein content, saturated and monounsaturated fatty acids, omega-3 (e.g., eicosapentaenoic acid) and omega-6 profiles, α- and β-carotene content, and complete amino acid profiles. Microbiological assessments (standard plate counts for anaerobes, coliforms, Salmonella, mesophilic spores, yeasts, and molds) and heavy metal screenings (Sb, As, Cd, Cu, Pb, Hg, Se, Sn, and Zn) were also conducted. Among the most notable results, E. radiata and Cladophora sp. exhibited low total fat content (1.56% and 1.8%, respectively). Ecklonia radiata was distinguished by its high carbohydrate content (62.48%) and essential amino acids, such as lysine (718.52 mg·100 g^–1), along with elevated omega-3 levels (especially eicosapentaenoic acid [9.3%]) and acceptable microbiological quality. Conversely, Cladophora sp. stood out for its high ash (60.9%), β-carotene (180 µg·100 g^–1), and arginine (750 mg·100 g^–1) content. However, its lower microbiological quality and elevated heavy metal levels suggest the need for caution when using it as a component in functional foods. The nutritional differences between these species suggest their complementary potential, opening important opportunities for the development of future functional food applications based on seaweeds.