Rheological properties of cholesterol-reduced, yolk-stabilized mayonnaise

The effects of cholesterol on droplet size distribution and rheological properties of cholesterol-reduced egg yolk-stabilized emulsions were determined. Oil-in-water emulsions were prepared by using spray-dried eggs submitted to different levels of cholesterol reduction (14–81 wt% of cholesterol removed). Cholesterol was extracted in a modified Jennings apparatus with subcritical CO2 (9°C and 4.66·106 Pa). Oscillatory and steady flow tests, as well as droplet size distribution measurements, were carried out on the cholesterol-reduced egg yolk-stabilized emulsions. The rheological parameters increased with the level of cholesterol reduction up to 40–80 wt% for emulsions having the same total amount of egg yolk. Opposite results, however, were obtined with some emulsions stabilized by a highly cholesterol-reduced (≈80 wt%) egg yolk. These results were explained by taking into account two opposite phenomena: an increase in the concentration of surface-active agents as cholesterol content decreased, and a lipoprotein structural rearrangement induced by cholesterol removal.