Ultrasound-enhanced extraction unlocks superior functional properties and bioactive profles in Fucus vesiculosus...

This study examined protein extraction from Fucus vesiculosus using both conventional and ultrasound-assisted extraction (UAE) methods, highlighting this seaweed's potential as a sustainable protein source. Both methods achieved optimal protein yields at 6 % alkali concentration, with UAE (43.98 % ± 0.49 %) producing a significantly higher yield compared to conventional extraction (39.29 % ± 1.66 %). UAE produced higher quality techno-functional properties proteins, as evidenced by several key findings. SDS-PAGE analysis showed protein distribution from 10 to 150 kDa, with conventional extraction yielding stronger bands than UAE across major molecular weight regions. Amino acid analysis showed a well-balanced profile with high concentrations of glutamic and aspartic acids and all essential amino acids. UAE significantly enhanced protein functionality by improving solubility across a broader pH range (9.41 % at pH 4 compared to 0.86 % for conventional extraction) and producing smaller, more stable particles (173.61-259.01 nm). Structural analyses using FTIR, fluorescence, and circular dichroism revealed that UAE induced partial protein unfolding and increased β-sheet content, which contributed to improved solubility, interfacial properties, and ultimately enhanced emulsifying and foaming properties. It also yielded higher levels of bioactive compounds, including phenolics (69.75 mg PGE/g) and antioxidants, with enhanced radical scavenging activities. While mineral content was higher in UAE samples, elevated arsenic levels require further investigation. Confocal laser scanning microscopy confirmed UAE's superior extraction efficiency through more uniform distribution of smaller protein particles. These findings demonstrate that UAE offers significant advantages over conventional methods for developing seaweed-based products with enhanced applications in food and pharmaceutical industries.