Ultrasonic modulation of amyloid fibrillization in Antarctic krill protein for enhanced iron delivery.

Ultrasonic treatment, as a controllable structural modification strategy, exhibits significant potential in regulating the protein metal-binding capacity. This study modulated amyloid fibrillization of Antarctic krill protein (AKP) via ultrasonication and constructed Fe2+-loaded composite carriers for enhanced iron delivery. Results showed that pre-heating ultrasonication (Upre-AF) significantly accelerated AKP fibrillization within 15 min. Secondary structure analysis revealed that both Upre-AF and post-heating ultrasonication (Upost-AF) samples displayed a trend of initial increase followed by a decrease in β-sheet content, along with a reduced particle size. These changes reflect a structural transformation and decreased aggregation degree, forming short, straight fibrils in Upre-AF and vermicular fibrils in Upost-AF. Ultrasonication significantly improved the iron-binding capacity of the fibrils by 29.81% (Upre-AF15-Fe) and 32.01% (Upost-AF5-Fe), and the resulting complexes exhibited excellent sustained Fe2+ release under simulated gastrointestinal digestion. This work provides a theoretical basis and data support for the application of AKP-derived amyloid fibrils in iron-fortified functional foods.