Elemental and Nutritional Characterisation with Vibrational Spectroscopy Analysis of Ulva sp., Gracilaria multipartita, and Sargassum muticum

Macroalgae are rich in bioactive compounds with potential therapeutic applications, including antioxidant, antimicrobial, and nutritional properties. In this study, the biochemical composition of three seaweed species—Ulva sp., Gracilaria multipartita, and Sargassum muticum—was analysed, focusing on their mineral content and macronutrient profile. The ash, protein, fibre, lipid, and carbohydrate contents ranged from (dw) 26.56 to 33.53 g/100 g, 10.13 to 18.43 g/100 g, 0.11 to 0.19 g/100 g, 5.83 to 10.88 g/100 g, and 42.48 to 53.27 g/100 g, respectively. The findings indicate that the species studied are excellent sources of essential minerals, particularly magnesium, potassium, calcium, sodium, and trace elements, such as iron, zinc, copper, and manganese. Sargassum muticum exhibited the highest mineral content and thus holds significant promise for further exploration in biomedical and therapeutic contexts. FTIR, FT-RAMAN, and FT-NIR analysis highlight the presence of proteins, lipids, carbohydrates, including cell wall phycocolloids, and phenolic compounds. These results underscore the potential of macroalgae as natural sources of bioactive compounds for health-related applications, highlighting their value beyond traditional dietary supplementation.