Characterization of seaweed, aqueous extract, and residue from Kappaphycus alvarezii cultivated in Brazil for potential industrial applications

This study aims to comprehensively characterize Kappaphycus alvarezii cultivated in S˜ao Paulo (SP) and Santa Catarina (SC), Brazil. Green and red seaweeds, along with aqueous extracts and residues post-extraction, were analyzed for total phenolic content (TPC), total flavonoid content (TFC), total carotenoids (TCN), carbohydrates, soluble sugars, starch, protein, carrageenan yield, heavy metals, nitrogen, biogenic amine profile, amino acids, and fatty acids. Nuclear magnetic resonance and UV–visible (UV-Vis) spectroscopy were also performed. Tukey’s test was used for mean comparison, principal component analysis and heatmap were employed to analyze the results. A wide variation of the concentration of analyzed compounds was observed in the different locations. Overall, seaweeds from SC presented a higher concentration of TPC, TFC, TCN, TC, TC, as well as carrageenan yield, while seaweeds from SP exhibited higher levels of most of the analyzed macro and micronutrients, as well as of polyamines and fatty acids. The residues showed, as well, differences between SP and SC samples, and different biotechnological applications can be suggested for this by-product. Results demonstrate the importance of considering the geographic origin and strain types of K. alvarezii when evaluating the chemical profile for optimizing potential biotechnological applications.