November 17/Lyngby, Denmark/Health & Medicine Week -- According to recent research published in the European Journal of Lipid Science and Technology, "The oxidative stability of fish oil-enriched light mayonnaise (40% oil) and the influence of two different emulsifiers, egg yolk and milk protein-based emulsifier, were evaluated. Moreover, the effects of different fish oil concentrations (4, 10 and 14%) and storage temperatures (2 and 20 degrees C) were investigated."

"As expected, the results showed that lipid oxidation increased with storage temperature, and at 20 degrees C with increasing fish oil concentrations. On the basis of the findings in this study, a storage temperature of 20 degrees C for four months cannot be recommended for light mayonnaise due to significant lipid oxidation even in mayonnaises without fish oil. However, enrichment of light mayonnaises with 4% fish oil without adding antioxidant did not result in increased oxidation when stored at 2 degrees C, and thus seems feasible; however, this has to be confirmed by sensory analysis. Surprisingly, our hypothesis that substitution of egg yolk with a less iron-containing emulsifier (milk protein-based emulsifier) could increase the oxidative stability of fish oil-enriched mayonnaises was not confirmed," wrote A.D.M. Sorensen and colleagues, Technical University of Denmark.

The researchers concluded, "That the initial quality of the emulsifiers was more important than its iron content in terms of lipid oxidation."

Sorensen and colleagues published their study in European Journal of Lipid Science and Technology ("Influence of Emulsifier Type on Lipid Oxidation in Fish Oil-enriched light Mayonnaise." European Journal of Lipid Science and Technology, 2010;112(9 Sp. Iss.):1012-1023).

For additional information, contact C. Jacobsen, Technical University of Denmark, National Institute Aquat Resources DTU Aqua, Sect Aquat Lipids & Oxidat, Bldg 221, DK-2800 Lyngby, Denmark.

From the November 29, 2010, Prepared Foods E-dition