title: Ultrasound effects on the assembly of casein micelles in reconstituted skim milk.
abstract: Reconstituted skim milks (10 % w/w total solids, pH 6·7-8·0) were ultrasonicated (20, 400 or 1600 kHz at a specific energy input of 286 kJ/kg) at a bulk milk temperature of <30 °C. Application of ultrasound to milk at different pH altered the assembly of the casein micelle in milk, with greater effects at higher pH and lower frequency. Low frequency ultrasound caused greater disruption of casein micelles causing release of protein from the micellar to the serum phase than high frequency. The released protein re-associated to form aggregates of smaller size but with surface charge similar to the casein micelles in the original milk. Ultrasound may be used as a physical intervention to alter the size of the micelles and the partitioning of caseins between the micellar and serum phases in milk. The altered protein equilibria induced by ultrasound treatment may have potential for the development of milk with novel functionality.
authors.affiliation: CSIRO Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: CSIRO Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
authors.forename: Pablo
authors.initials: P
authors.lastname: Juliano
authors.affiliation: CSIRO Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
authors.forename: Roderick P W
authors.initials: RP
authors.lastname: Williams
authors.affiliation: School of Applied Sciences, College of Science, Engineering and Health, RMIT University, Victoria 3001, Australia.
authors.forename: Julie
authors.initials: J
authors.lastname: Niere
authors.affiliation: CSIRO Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, Victoria 3030, Australia.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Augustin
mesh_terms: D000818:Animals; D002364:Caseins / Q000737:chemistry*; D005511:Food Handling / Q000379:methods*; D057141:Food, Preserved; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D008892:Milk / Q000737:chemistry*; D010316:Particle Size; D066329:Protein Aggregates; D012995:Solubility; D013010:Sonication; D013016:Sound
chemical_list: D002364:Caseins; D008823:Micelles; D066329:Protein Aggregates