Effect of Flow Field (Stirring) on the Heat-Induced Fibrillogenesis of β-Lactoglobulin in the Presence of Glucose at Neutral pH

The effect of stirring on the amyloid fibrillogenesis of β-Lactoglobulin (βLG) at pH 7 was studied in the presence of glucose (Glu). Fibrillogenesis was carried out by heating the 0.30 mM βLG solution at pH 7 with and without glucose (37.5 mM) for 24 hrs at ≥80°C under stirring (250 and 474 rpm) conditions. For control samples, βLG solutions with and without glucose were incubated under unstirred conditions. The flow-induced birefringence method was used to characterize the fibrillogenesis, revealing the coil-stretch transition and pointing out the existence of worm-like flexible fibrils in all samples. Atomic Force Microscopy (AFM) was used as a morphology that clearly showed the flexible fibrils in all samples and also revealed that the fibril lengths shortened on increasing the stirring rate. This shortening in lengths might be possible due to weak hydrophobic interaction at pH 7 resulting in fragmentation of fibrils over stirring. Glucose inhibited the fibrillogenesis of βLG even on stirring.