Size reduction of "reformed casein micelles" by high-power ultrasound and high hydrostatic pressure
Yacine Hemar1, Cheng Xu2, Sinong Wu3
1School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; The Riddet Institute, Palmerston North, New Zealand.
Abstract:
We investigated the effect of ultrasound (US) and high hydrostatic pressure (HHP) on the size of reformed casein micelles (RMCs) obtained by titrating calcium and phosphorous solution into sodium caseinate solutions. Both US and HHP reduced the size of the RMCs. A decrease in size from ~200 nm to ~170 nm when US (20 kHz, 0.46 W/mL) was applied for 30 min; and down to ~85 nm when HHP was applied 500 MPa for 15 min. Electron microscopic analysis showed that the RMCs before and after US are similar to milk native casein micelles, and that HHP extensively disintegrated the RMCs. Small angle X-ray scattering and SDS-PAGE showed that the internal structure of the RMCs as well as the casein molecules are not affected by the US and HHP treatments.
