β-Lactoglobulin nanofibrils: The long and the short of it

The bovine whey protein β-lactoglobulin will self-assemble into amyloid-like nanofibrils when heated at pH ≤ 3 and temperatures ≥75 °C. These fibrils have diameters <10 nm and lengths that can exceed 10 μm. The length and stiffness of fibrils depends on ionic strength; heating at low ionic strength produces long semi-flexible fibrils, whereas heating with added salts produces highly flexible 'worm-like' fibrils that are an order of magnitude shorter. Over the last two decades there has been a substantial research effort focused on imaging fibrils, manipulating conditions to accelerate fibril formation, and characterising microstructural and rheological properties of fibril dispersions. Here we review the major mechanistic findings, explore potential applications for fibrils as food ingredients, and highlight the major gaps in knowledge surrounding these intriguing self-assembled structures.