Influence of emulsifier type on lipid oxidation in fish oil-enriched light mayonnaise

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 4 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. These findings suggest that the initial quality of the emulsifiers was more important than its iron content in terms of lipid oxidation.