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

Abstract

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 (U_pre-AF) significantly accelerated AKP fibrillization within 15 min. Secondary structure analysis revealed that both U_pre-AF and post-heating ultrasonication (U_post-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 U_pre-AF and vermicular fibrils in U_post-AF. Ultrasonication significantly improved the iron-binding capacity of the fibrils by 29.81% (U_pre-AF15-Fe) and 32.01% (U_post-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.