Impact of pulsed electric field technology on whey protein isolate

A commercially available pulsed electric field (PEF) system has been used to treat a 23% total solids solution of whey protein isolate (WPI) before spray drying. The 3 trials conducted for this study used PEF parameters within the range of 17-21 kV/cm for field strength and 8-15 kJ/L for specific energy. PEF treatment led to a decrease in solution viscosity by as much as 32.8% within 24 h., increased the solubility of spray-dried powder up to 12.2%, and increased the emulsifying activity index (EAI) and emulsion stability index (ESI) by 6.5 times and 250%, respectively, as compared with the non-PEF control. Assessment of protein structure was conducted by gel electrophoresis, circular dichroism (CD), fluorescence spectroscopy, and differential scanning calorimetry (DSC) with only a minor effect on β-strand by CD with the highest PEF treatment, medium and high PEF treatments affected fluorescence intensity, and increased enthalpy associated with denaturation by DSC. These minor changes may explain the changes in physical and functional properties for the PEF treated WPI. This study provides physical and functional property data for the first instance of commercially relevant concentrated WPI being treated through a PEF flow cell at a rate of 170 L/hr.