Small deformation properties of model salad dressings prepared with reduced cholesterol egg yolk

Low-fat, low-cholesterol materials were extracted from spray-dried egg yolk using as solvents petroleum ether, petroleum ether/ethanol, ethanol/water, and supercritical CO2. The four extracts and their source (spray-dried yolk) were incorporated into traditional recipes for oil in water salad dressings. The linear viscoelasticity of these systems was characterised by dynamic oscillation and creep/relaxation curves on a stress-controlled Carri-Med rheometer. The high protein content of the extracts generates stronger and more elastic structures than those of commercial salad dressings but they are comparable to the viscoelastic properties of commercial mayonnaises which contain high cholesterol egg yolk. Measurements of the size of oil droplets over a period of eleven days demonstrate that these emulsions maintain acceptable consistency. The methodology adopted and the conclusions derived might assist in the purposeful formulation of low cholesterol salad dressings.