Ameliorating effect of γ-aminobutyric acid on the physical performance of whey protein films

γ-Aminobutyric acid (GABA) is a non-protein amino acid that possesses various health benefits. In this study, whey protein isolate (WPI)-based films incorporated with GABA at different concentrations (0, 0.1, 0.5, and 1.0% w/v) were characterized for color, water vapor permeability (WVP), microstructure, GABA leachability, and hydration, optical, mechanical and thermal properties. All the tested WPI films exhibited a colorless and transparent appearance. The addition of GABA increased the elongation at break and WVP while decreased tensile strength and light transmittance of the WPI films. The hydration and thermal properties of the WPI films were enhanced when low concentrations of GABA (0.1, 0.5% w/v) were incorporated, but were impaired in the presence of 1.0% (w/v) GABA. This was attributed to the different microstructures of the WPI films at different GABA concentrations. Our findings demonstrated that GABA could be a promising ingredient for improving the physical properties of WPI films.