Effects of homogenisation pressures on physicochemical changes in different layers of ultra-high temperature whole milk during storage

The objective of this study was to investigate the effects of homogenisation pressures (10, 20, and 30MPa) on the physicochemical changes in top, middle and bottom layers of ultra-high temperature whole milk stored at 25 degrees C for 6months. Fat separation, fat globule sizes, fat and protein contents, viscosity, free amino acids content and pH were analysed at an interval of 15days. Results showed that higher homogenisation pressure retarded the differentiations of milk fat globule sizes, fat and protein contents and viscosity in different milk layers, but did not affect the final fat separation, proteolysis and pH.