Amyloid fibril-templated oleogels

Abstract

Oleogelation based on nutritionally valuable ingredients enables liquid oils to target various food and material applications where fat-like functionality is required. The present study offers a novel approach to design oleogels with high oil content (up to 98 %) structured by food protein amyloids at low concentrations. This was achieved by Pickering stabilization of oil-in-water emulsions with different food amyloid fibrils from both animal and plant proteins, followed by dehydration of finely dispersed high internal phase emulsions. The hydrophobic phase was constituted by either rapeseed or medium-chain triglyceride (MCT) oils, whereas whey, soy and potato amyloid fibrils were formed via heat-induced acidic hydrolysis. First, we studied how animal and plant proteins self-assemble into amyloid fibrils with tuneable morphological and surface properties. The emulsifying performance of the amyloid fibrils was then investigated by light microscopy, particle size distribution and viscosity. Finally, we characterised the composition, microscopical and rheological properties of amyloid fibril-templated oleogels, emphasising oil encapsulation efficiency. We demonstrate that the ensued solid-like edible oleogels have a shear elastic modulus of the order of 10 4 –10 5 Pa. Mesoscopic characteristics and surface properties of the amyloid fibrils allow tuning the rheological characteristics, encapsulation efficiency and interfacial protein concentration in the oleogels. Fibrillization offers a robust strategy for solidifying liquid oil with high efficiency and stability of the oleogels. The present approach opens multifaceted applications of amyloid fibril-based oleogels in food, biomedical, and pharmaceutical fields, such as plant-based shortenings, ointments, tissue scaffolds, and controlled release drug delivery systems. • Amyloid fibrils structure liquid oils at low concentration • Whey, soy, and potato amyloid fibrils at pH 2 have high oleogelation capacity • Plant-based amyloid fibrils encapsulate oil up to 98 % • Oleogels structured by amyloids entrap oil into polyhedral droplets of ∼2 μm • Amyloid fibrils morphology tunes the structuring of liquid oils • Oleogels show solid-like behaviour with shear moduli of 10 4 –10 5 Pa

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