The autoxidation of certain polyunsaturated triglycerides (PUFA-TG) such as fish oils was inhibited effectively by the addition of 5 % soybean phospholipids (PL) to PUFA-TG used as a substrate. The antioxidative effect of PL became greater with increase in phosphatidylcholine (PC) content in PL. The antioxidative effect of mixed tocopherol (Toc) also increased synergistically by adding 0.1 % Toc and 1 % PL to the substrate.
The effects of each phospholipid class such as PC, phosphatidylethanolamine (PE) and phosphatidic acid (PA) were assessed, PC had antioxidative effect and PE, synergistic effect on Toc and PC, PA showed no effect on the autoxidation of PUFA-TG.
The strongest antioxidative effect of PC and PE mixture was observed for PUFA-TG when PC was mixed with PE at a ratio of 20 : 1. Remarkable synergistic effects on Toc were observed at ratios of 4 : 1, 2 : 1 and 0 : 1 of PC and PE mixtures.
Based on the present results, antioxidative behavior of PL would appear due to the nitrogen containing moiety and not to the phosphoric acid moiety of the PL structure.