The antioxidant role of selected polysaccharides was studied in the continuous phase of a Menhaden oil-in-water emulsion coated by polyoxyethylene(23) lauryl ether (Brij 35) at neutral pH. The addition of low-methoxyl (LM) and high-methoxyl (HM) pectin (0.02-0.1 wt %) reduced the formation of lipid hydroperoxides and thiobarbituric acid reactive substances with an inhibition that increased with increasing polysaccharide concentration in the continuous phase. alpha-Carrageenan and sodium alginate were less effective antioxidants than pectin and were prooxidative under certain conditions. None of the polysaccharides impacted the physical properties of the emulsions as determined by droplet particle size (d(43) approximately 0.32 microm) and creaming index. LM and HM pectins had higher iron-binding capacities as compared to alpha-carrageenan and sodium alginate, which may relate to their higher antioxidant activities. These results suggest that the addition of anionic polysaccharides to the continuous phase of oil-in-water emulsions could be used to increase the oxidative stability of oil-in-water emulsions and thus prolong shelf life.