The antioxidant mechanisms of whey proteins in a Tween 20-stabilized salmon
oil-in-water emulsion were investigated. The antioxidant activity of the h
igh molecular weight (HMW) fraction of whey from pasteurized milk was found
to increase with concentration, as determined by its ability to inhibit TB
ARS and lipid peroxide formation. The ability of sulfhydryl-blocked whey to
inhibit TBARS formation was reduced 60% compared to the HMW fraction alone
at 7 days of storage. HMW fraction was able to scavenge peroxyl radicals,
with scavenging decreasing approximately 20% when sulfhydryls were blocked.
HMW fraction was able to chelate iron away from the surface of negatively
charged BSA-stabilized emulsion droplets, indicating that the whey proteins
were able to chelate iron. A better understanding of the mechanisms by whi
ch whey proteins inhibit lipid oxidation could increase the use of whey pro
teins as food antioxidants.