Characterization of lactoferrin oil-in-water emulsions and their stability in recombined milk.
Emulsions were prepared with 20% soy oil and different concentrations of lactoferrin, and tested at pH values from 3 to 7·5. The stability of the emulsions decreased as the pH got closer to the isoelectric point of the protein. A concentration of 1% lactoferrin was determined to be sufficient to provide full coverage of the emulsion droplets. Lactoferrin-stabilized emulsions were then prepared in water at pH 6·6 and their behaviour when added to reconstituted milk was studied. It was observed that lactoferrin emulsions were stable when reconstituted in milk, but they showed aggregation when diluted in milk serum alone. The destabilization was caused by shielding of the charges on the surface of the oil droplets. Stabilization in milk occurred due to interactions at the interface with other soluble proteins. In fact, when β-lactoglobulin or sodium caseinate were added to the serum, stability of the emulsion droplets was restored, indicating that these proteins were able to adsorb at the interface and aid in the stabilization. Since ζ-potential measurements did not show significant overall charge on the emulsion droplets, this suggests that the stabilization forces are not only electrostatic in nature, but that there are other mechanisms at play.
Acero-Lopez
A
A
Food Science Department, University of Guelph, Guelph, Ontario.
Schell
P
P
Corredig
M
M
Alexander
M
M
D000327:Adsorption; D000818:Animals; D002417:Cattle; D004655:Emulsions; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000737:chemistry*; D008892:Milk / Q000737:chemistry*; D013024:Soybean Oil / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D004655:Emulsions; D014867:Water; D013024:Soybean Oil; D007781:Lactoferrin