Fibrillization kinetics and rheological properties of panda bean (Vigna umbellata (Thunb.) Ohwi et Ohashi) protein isolate at pH 2.0

• Published in: International journal of biological macromolecules 2023-02, Vol.228, p.816-825
• Main Authors: Ge, Jiao, Sun, Cuixia, Li, Saiya, Deng, Nianxiang, Zhang, Yin, Fang, Yapeng
• Format: Article
• Language: English
• Subjects: Amyloid - chemistry; Amyloid fibrils; Circular Dichroism; Fibrillation kinetics; Gel electrophoresis; Hydrogen-Ion Concentration; Kinetics; Molecular mechanism; Panda bean protein isolate; Plant Proteins - chemistry; Rheological properties; Vigna - metabolism
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2022.12.165

Recently, research interests are growing regarding the formation and mechanisms of amyloid fibrils from plant proteins. This study investigated the fibrillization kinetics and rheological behaviors of panda bean protein isolate (PBPI) at pH 2.0 and 90 °C for various heating times (0–24 h). Results showed that PBPI formed two distinct classes of fibrils after heating for 10 h, including flexible fibril with a contour length of ∼751 nm, and rigid fibril with periodicity of ∼40 nm. The secondary structural changes during fibril formation were monitored by circular dichroism spectroscopy and indicated that β-sheet content increased first (0−12 h) and then decreased (>12 h), which coincided with similar changes in thioflavin T fluorescence. The gel electrophoresis revealed that the polypeptides of PBPI were progressively hydrolyzed upon heating, and the resulting short fragments were involved in fibril formation rather than PBPI monomer. PBPI-derived fibrils showed extremely high viscosity and storage modulus. A plausible molecular mechanism for PBPI fibrillation process was hypothesized, including protein unfolding, hydrolysis, assembly into matured fibrils, and dissociation of the fibrils. The findings provide useful information to manipulate the formation of legume proteins-based fibrils and will benefit future research to explore their potential applications. [Display omitted] •The self-assembling behavior of PBPI was time-dependent at 90 °C and pH 2.0.•PBPI self-assembled into flexible fibril and rigid fibril.•PBPI-derived fibrils possessed extremely high viscosity.•PBPI-derived fibrils showed excellent gelling performances.•PBPI fibrillation included unfolding and hydrolysis, aggregation, and disintegration.