title: Formation of interfacial milk protein complexation to stabilize oil-in-water emulsions against calcium.
abstract: Oil-in-water emulsions (30% soya oil) stabilized by sodium caseinate or whey protein were destabilized in the presence of calcium, whereas lactoferrin-stabilized emulsion was stable under same conditions. At pH7, addition of lactoferrin to the caseinate or whey protein-stabilized emulsions led to association of lactoferrin with adsorbed proteins by electrostatic interactions, hence resulted in the formation of lactoferrin-caseins/whey protein interfacial complexes at the interface of the emulsion droplets. The stability of the interfacial complexes-coated emulsion droplets in the presence of Ca(2+) was examined by determination of particle size, zeta-potential and microstructure as a function of Ca(2+) concentration and added lactoferrin concentration. For emulsions made with 1% w/w caseinate or WPI, the stability of emulsions in the presence of 20 mM CaCl(2) has been improved markedly after addition of 0.2% w/w lactoferrin, suggesting the small amount of lactoferrin on the interface can largely enhance the calcium stability of milk proteins-coated emulsion droplets. Steric repulsion between the interfaces of droplets produced by the large lactoferrin molecules on the interface was considered to contribute the preventing the flocculation caused by Ca(2+) binding and reduction in the electrostatic repulsion between the emulsion droplets.
authors.affiliation: Riddet Institute, Massey University, Palmerston North 4442, New Zealand. a.m.ye@massey.ac.nz
authors.forename: Aiqian
authors.initials: A
authors.lastname: Ye
authors.forename: Jerilyn
authors.initials: J
authors.lastname: Lo
authors.forename: Harjinder
authors.initials: H
authors.lastname: Singh
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002364:Caseins / Q000737:chemistry*; D004655:Emulsions; D007781:Lactoferrin / Q000737:chemistry*; D010316:Particle Size; D013024:Soybean Oil / Q000737:chemistry*
chemical_list: D002364:Caseins; D004655:Emulsions; D013024:Soybean Oil; D007781:Lactoferrin; D002118:Calcium