Mechanistic elucidation of soy protein fibrils formation and growth: Critical roles of pH-shifting treatment and soy protein isolate concentration.
- 2026-02
- International journal of biological macromolecules 344
- PubMed: 41565132
- DOI: 10.1016/j.ijbiomac.2026.150398
Study Design
- Methods
- pH-shifting pretreatment applied to soy protein isolate (SPI) at concentrations 10, 30, and 50 mg/mL; analyses include SDS-PAGE, ThT fluorescence, FTIR, CD, fluorescence spectroscopy, surface hydrophobicity, average particle size, zeta potential, and TEM.
This study systematically examined how pH-shifting pretreatment influences the formation mechanism of soy protein isolate (SPI) fibrils (SPF) across varying concentrations (10, 30, and 50 mg/mL). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that pH-shifting converts more macromolecular peptides in SPI into small-molecule peptides. ThT fluorescence revealed that increasing SPI concentration and applying pH-shifting pretreatment produced more β-sheet structures in SPF. FTIR and CD analyses demonstrated that pH-shifting promotes fibril formation through α-helix-to-β-sheet transitions, with minor contributions from disordered structures adopting β-sheet conformations. Fluorescence spectroscopy and surface hydrophobicity results indicated that hydrophobic interactions are critical for converting SPI into SPF. Analysis of average particle size and zeta potential revealed that pH-shifting treatment increased electrostatic repulsion, inducing structural unfolding and protein fibril conversion up to 72.61%. TEM analysis showed that pH-shifting treatment and higher SPI concentration enhanced the diameter and length of SPF, producing a more coiled and entangled morphology that formed a dense network, ultimately increasing system viscosity. Elevating SPI concentration combined with pH-shifting is therefore an effective pretreatment approach that not only facilitates SPF formation but also modulates its morphological characteristics, with their synergistic effects markedly enhancing SPF growth.
Research Insights
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