Ultrasound‐induced changes in physical and functional properties of whey proteins

Summary Use of high‐intensity ultrasound to modify certain functional properties of whey proteins is an alternative to traditional method in food industry. Whey protein isolate (WPI) solutions were treated with an ultrasound probe (20 kHz) at different intensities (20% or 30% amplitude) and durations (10 or 20 min). Results showed that ultrasound treatment changed physical and several functional properties of whey proteins including decreased particle size (from 190.4 nm to 138.0 nm), increased surface hydrophobicity (from 5.13 × 105 to 5.77 × 105), free sulphydryl groups (from 52.64 μmol SH g−1 to 53.64–58.77 μmol SH g−1), solubility (from 74.95% to 89.70%), emulsion activity index (from 3.18 m2 g−1 to 3.59–5.32 m2 g−1) and emulsion stability index (from 62.26 min to 71.44–104.83 min), and changed viscosity (from 5.51 mPa.s to 4.81–5.64 mPa.s). Therefore, we conclude that high‐intensity ultrasound can be potentially applied to whey proteins to improve its specific functions during food processing.