ABSTRACTA study on the effect of exogenously added 2 anionic phospholipids, phosphatidylserine (PS), and phosphatidic acid (PA), against lipid oxidation in food systems was carried out using cooked beef homogenate and emulsified sardine oil. Measurements of thiobarbituric reactive‐substances (TBARS) showed a pronounced inhibitory effect of egg yolk PA and dipalmitoyl PA on the oxidation of beef homogenate during storage at 4 EC for 6 d. The addition of dipalmitoyl PA to emulsions of fish oil effectively suppressed the hemoprotein‐induced lipid oxidation. Meanwhile, the addition of dipalmitoyl PA and bovine brain PS to emulsions of fish oil suppressed the nonheme iron ion‐induced lipid oxidation. Therefore, the unique protective effect of PA against the oxidation of beef homogenate could be partly explained by the suppression of the catalytic activity of nonheme iron and hemoprotein. Abbreviations Used: BBPS, bovine brain phosphatidylserine; DPPS, dipalmitoyl phosphatidylserine; DPPA, dipalmitoyl phosphatidic acid; EYPA, egg yolk phosphatidic acid; EYPC, egg yolk phosphatidylcholine; PE, phosphatidylethanolamine; TBARS, thiobarbituric acid‐reactive substances; Hepes, 2‐[4‐(2‐hydroxyethyl)‐1‐piperazinyl] ethanesulfonic acid; LPC, lysophosphatidylcholine; LPE, lysophosphatidylethanolamine; TLC, thin‐layer chromatography.