Effect of pulsed electric field on structural modification and thermal properties of whey protein isolate

This study evaluated structural modification and thermal properties of whey protein isolate (WPI) treated by pulsed electric fields (PEF). Structural modification and thermal properties of WPI were evaluated by using fluorescence spectroscopy and differential scanning calorimetry (DSC) techniques. The effect of PEF treatments (electric field intensity ranging from 12, 16 and 20 kV cm and pulses ranging from 10-30) on intrinsic tryptophan fluorescence and extrinsic 1-anilino-naphthalene-8-sulfonate (ANS) fluorescence of WPI were studied. PEF treatments of WPI resulted in an increase in intrinsic tryptophan fluorescence intensity and 2-4 nm red shifts. There was an increase in extrinsic ANS fluorescence intensity which showed increases in the surface hydrophobicity of WPI. The apparent enthalpy and denaturation temperatures of PEFtreated WPI samples were modified by PEF treatments. Whey protein was denatured by approximately 43.7% when WPI was treated by PEF at the electric field intensity of 20 kV cm and 30 pulses. The results of this study indicated that PEF treatments affected structural modification and thermal properties of whey protein isolates.