Effect of pulsed electric field and thermal treatment on the physicochemical and functional properties of whey protein isolate

The effect of pulsed electric field (PEF) compared with thermal treatment on physicochemical properties (protein aggregation, surface hydrophobicity, contents of exposed and total sulphydryl groups, and thermal stability), and functional (emulsification and gelation) properties of whey protein isolate (WPI) was determined. Within the experimental conditions tested, PEF treatment did not affect any of the physicochemical or emulsification properties of WPI. However, the heat-induced gel strength of WPI decreased from 461 Pa to 139 and 67 Pa after PEF treatment at 30 kV cm−1 for 19.2 and 211 μs, respectively, and the corresponding gelation times increased from 40.8 min to 43.2 and 47.9 min. This study indicates that the effect of PEF on the gelation properties of WPI may be beneficial in applications where whey protein precipitation and gelation are not desirable, such as during concentration of whey protein preparations and prior to spray drying.