Investigating the fibrillation behavior of Spirulina platensis protein: Self-assembly process and effects on emulsion stability

Amyloid fibrils, characterized by their high aspect ratio and superior surface activity, present significat potential for stabilizing emulsion. This study investigated the effects of varying heating times on the structural transitions and emulsion stability of Spirulina platensis protein fibrils (SPPFs). SDS-PAGE analysis demonstrated that SPPFs formation was time-dependent. Atomic force microscopy (AFM) images showed a transition from spherical particles to fibrils. Thioflavin T (ThT) fluorescence, Nile red fluorescence, Congo red binding spectra, and FTIR spectroscopy indicated increased β-sheet content, reaching a maximum at 16 h. The ThT kinetics of SPPFs followed a pseudo-second-order model. Changes in intrinsic fluorescence and surface hydrophobicity were observed during fibril formation. Particle size and ζ-potential measurements confirmed enhanced dispersion stability at 16 h. Emulsions stabilized by SPPFs exhibited improved stability under alkaline conditions, low ionic strength, and thermal stress. These findings highlight the potential of SPPFs as effictive emulsifiers for emulsion-based food products.