We compared the electrical conductivity from two different aggregates of whey protein concentrates (WPC) film: conventional amorphous aggregation at natural pH (pH 6.5) and amyloid fibrils at a low pH (pH 2.0) far away from the isoelectric point. The two types of film fabricated by these solutions with different aggregate structures showed large variations in electrical conductivity and other properties. The WPC fibril film (pH 2.0) exhibited higher electrical conductivity than that of the conventional WPC film (pH 6.5), improved mechanical properties and oil resistance, due to varying morphology, higher surface hydrophobicity and more (absolute value) surface charge of film-forming solutions. The evidence from this study suggests that fibrilized WPC with high-ordered and β-sheets-rich structures fabricated high electrical conductivity film, which broadens the potential application of fibrils as functional bio-nanomaterials.
Keywords: Electrical conductivity; Fibril; film; whey protein concentrate.