Antioxidant effect of egg yolk on linoleate in emulsions.

Abstract

The antioxidant activity of whole egg, egg albumen and egg yolk was estimated, and it was found that egg yolk had strong antioxidant activity on linoleate in an emulsion both with and without Fe2+. The relationship between the antioxidant activity and the components of the egg yolk was also investigated. The low-density lipoprotein (LDL) fraction of yolk had very weak activity, the granule fraction having the strong antioxidant activity in egg yolk. Phosvitin, a potent antioxidant, had weak activity in this system, but it was elevated by combining with the LDL fraction. When egg yolk was heated at 80°C for 30 min, its activity decreased. These results suggest that egg yolk had an antioxidant effect on linoleate in emulsions with and without Fe2+, and that granules, and not LDL, were the strong antioxidant fraction of egg yolk. Furthermore, it is suggested that both a phosvitin and native lipoprotein structure may be necessary for the antioxidant activity of the yolk granules.