Tuning the extraction methodology targeting protein-enriched fractions from red algae

Abstract

Alternative protein sources are being studied to substitute animal protein production and decrease the environmental issues that are inherent to the production of animal-based foods. This study investigates the potential of red macroalgae (Gracilaria verrucosa, Porphyra dioica, and Palmaria palmata) as an eco-friendly alternative protein source. Using the Osborne fractionation methodology, proteins were extracted under varying parameters (pH and grinding) and techniques (ultrasound and enzymatic extractions). Seaweed proteins exhibited a strong affinity for water and alkaline environments. Optimal extraction yields were obtained with H2O for G. verrucosa (33.24 ± 1.81 g protein/100 g algae protein) and P. palmata (29.56 ± 1.73 gprotein/100 galgae protein), while P. dioica showed highest yields with aqueous 0.1 M NaOH (26.28 ± 5.90 gprotein/100 galgae protein). Molecular weight patterns revealed aggregates (> 200 kDa) in G. verrucosa and P. palmata in the 0.1 M NaOH fraction. H2O extracts displayed peaks (4884 kDa) linked to phycobiliproteins, showcasing good emulsifying properties. Solubility varied with solvents, with saline and 70 % EtOH dissolving lower molecular weight proteins. Aqueous 0.1 M NaOH extracts demonstrated promising texturizing capacity. Overall, proteins from red macroalgae show potential for food product development, offering an alternative with lower environmental impact compared to conventional animal-based proteins.