Advancing red seaweed Palmaria palmata as a next-generation protein source

Red seaweed (Palmaria palmata), abundant along the northern Atlantic and Pacific coasts, contains 8-35% protein. However, it has not been regarded as a dietary protein source due to the lack of effective methods for extracting proteins with high yield and purity. In this presentation, we discuss our recent research progress on the extraction and characterization of proteins from P. palmata.

Our study demonstrated that, compared to the control, microwave digestion (500 W, 30 min, MW) and acid hydrolysis (2 M HCl, 95 ºC, 2 h, AH) significantly increased the protein extraction yield from 10.4±0.4% to 47.6±3.4% and 46.5±3.9%, respectively. This improvement can be attributed to modified seaweed microstructures, including increased surface area, pore formation, and cell wall breakdown, as observed through scanning electron microscopy and confocal laser scanning microscopy images.

MW and AH treatments had distinct effects on the techno-functionalities of the extracted proteins. For example, at pH 7.0, the water solubility of MW and AH samples was slightly less than that of control. However, at alkaline pH ( >8.0), the solubility of three samples increased significantly. Additionally, MW and AH significantly reduced water-holding capacity from 6.0±0.0 to 1.9±0.1 and 3.1±0.1, respectively (P< 0.05), while showing a slight increase in fat holding capacity compared to the control (P >0.05). The emulsifying capacities of MW and AH proteins were approximately 2.0 and 1.8 times higher than the control, accompanied by increases of 2.0% and 24.5% in emulsifying stability. MD and AH-treated proteins exhibited unfolding and flexible structures, as evidenced by reduced α-helix content, increased random coils, elevated free sulfhydryl content, and a red shift in fluorescence spectra.

This work underscores the potential of P. palmata-derived proteins as value-added food ingredients, contributing to the exploration of novel and sustainable protein sources.