Impact of tween 20 hydroperoxides and iron on the oxidation of methyl linoleate and salmon oil dispersions

To determine the role of surfactant hydroperoxides on the oxidative stabili ty of fatty acids, the oxidation of methyl linoleate micelles and salmon oi l-in-water emulsions was measured as a function of varying Tween 20 hydrope roxide concentrations. Increasing Tween 20 hydroperoxide concentrations fro m 3.5 to 14.7 mu mol hydroperoxide/g Tween 20 decreased the lag phase of he adspace hexanal formation but did not increase the total amount of hexanal formed in methyl linoleate/Tween 20 micelles. In the micelle system, Fe2+ d ecreased the lag phase of hexanal formation but increased total hexanal con centrations only in micelles with the highest Tween 20 hydroperoxide concen trations (14.7 mu mol hydroperoxide/g surfactant). Increasing Tween 20 surf actant hydroperoxide concentrations also increased the oxidation of salmon oil-in-water emulsions as determined by lipid hydroperoxides and headspace propanal. In both the micelle and emulsion systems, the prooxidant effect o f Fe2+ decreased with increasing Tween 20 hydroperoxide concentrations. The se data show that surfactant hydroperoxides such as those in Tween 20 could decrease the oxidative stability of lipids in food emulsions.