Utilization of peanut protein isolate amyloid-like fibers as stabilizers for high internal phase Pickering emulsions

Abstract

This paper focuses on modifying peanut protein isolate (PPI) through fibrillation to enhance its emulsification properties and investigates the potential application of the fibers in stabilizing high internal phase Pickering emulsions (HIPPEs). Th T result indicates that the optimal conditions for peanut protein isolate amyloid-like fibers (PAFs) preparation are pH=2, 90 °C, and 20 h. Electrophoresis and Transmission electron microscope demonstrate that PPI undergoes peptide hydrolysis and self-assembly during the reaction process, leading to the formation of an elongated linear structure with a diameter approximately 14 nm. Furthermore, infrared spectroscopy, X-ray diffraction, and contact angle results further demonstrate an increase in β-sheet content, crystallinity, and surface hydrophilicity compared to PPI. Notably, the emulsification activity index (EAI) of PAFs (78.62 ± 1.68 m2/g) was found to be increased up to threefold compared to that of PPI (27.89 ± 1.98 m2/g). According to visual observation and microstructural analysis, the addition of 1% PAFs has been found to effectively stabilize HIPPEs (φdisp = 0.75) due to the presence of dense protective layers formed by PAFs. Additionally, the particle size results (D[3,2] = 17.02 ± 2.02 μm) also indicate that the oil droplets are tightly enveloped by the dense protective layers formed by PAFs. Moreover, rheological data indicates that HIPPEs stabilized using PAFs exhibit excellent solid-like viscoelastic behavior. Overall, these findings suggest that the utilization of PAFs has significant potential in enhancing the stability of HIPPEs.