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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.

The objective of this study was to destabilize the protein–lipid complex in egg yolk precipitate obtained after the removal of soluble proteins, referred to as the pellet, through enzymatic treatment for further phospholipids extraction. A combination of proteolytic and lipolytic enzymes was applied to release the lipids from the pellet or weaken the pellet emulsion. Emulsions prepared using Protease P/Lipase AY30, Protease II/Lipase AY30 and Protease M/Lipase AY30 treated pellets had larger oil droplets (78, 65, 56 µm) and higher coalescence rates (51, 41, 35 %) than those of Protex 51FP, pellet, Protex 7L and Protease A with oil droplet size of 20, 18, 15 and 13 µm and coalescence rates of 31, 8, 7.5 and 8 %, respectively. Cream and liquid subnatant fractions obtained after further centrifugation of hydrolysates were subjected to lipid analyses. Over 90 % of phosphatidylcholine (PC) present in the pellet and 80 % of that in the original egg yolk were recovered in the cream from Protease P/Lipase AY30 treatment, while the recovery of PC from the egg yolk was significantly lower in creams from Protex 7L or Protease 51FP treatments (12 and 10 %, respectively). Pellets treated with Protease M, Protex 7L or Protex 51FP in combination with Lipase AY30 led to a significant loss of PC due to the conversion of PC to lysophosphatidylcholine or its degradation. Cream fractions obtained from the study represented a better material for the recovery of PL than intact egg yolk using environmentally‐friendly techniques such as supercritical carbon dioxide (SC‐CO2) extraction.