Exploring the self-assembly journey of oat globulin fibrils: From structural evolution to modified functionality

Self-assembling protein fibrils are promising supramolecular structures. In particular, oat globulin (OG) has demonstrated considerable potential as a sustainable fibril resource derived from plant-based proteins. This study investigated the dynamic evolution of OG fibrils during their formation, including structural and functional properties. To this end, OG fibrils were formed and multiplied through acidic thermal treatment (3% w/w, pH 2, 90 °C), as reflected by an increase in the thioflavin T (ThT) fluorescence, altered particle size distribution, and microscopic morphology. During fibrillation, OG underwent structural unfolding and hydrolysis into polypeptides and was then re-assembled into fibrils enriched in β-sheet structures (from 37.99% at 0 h to 42.18% at 24 h). Based on the zeta potential, surface hydrophobicity, and sulfhydryl content results during fibrillation, the self-assembly process of OG was driven by disulfide bonds as well as electrostatic and hydrophobic interactions. During fibrillation, OG fibrils exhibited higher viscosity, altered emulsifying properties, and increased antioxidant function. Moreover, OG fibrils did not elicit in vitro cytotoxicity. Collectively, this study provides novel insights into the structural characteristics and formation mechanism of OG fibrils.