Effects of Fatty Chains on Antioxidant Properties of Fish Phospholipids

点击翻译按钮获取中文摘要

It has been known that oxidation rate of lipids in skin is higher than that in white muscle of sardine and mackerel during cold storage. However, the cause of the difference in oxidation rates of the lipids has not been clearly elucidated. In the present study, effects of lipid constituents on stability for oxidation of Total Lipids (TL) extracted from the different tissues of sardine were investigated. The oxidation rate of sardine TL was influenced by Alpha-Tocopherol (Alpha-Toc) content, phospholipid content and fatty acid composition of the TL : the higher the alphaーToc content the lower the oxidation rate of the TL. Sardine Non-polar Lipids (NL) containing added alpha-Toc at 30 mug/100g decreased in oxidation rate, when either sardine Polar Lipids (PL) or sardine Phosphatidyl-Ethanolamine (PE) were added to the NL, while addition of Phosphatidyl-Choline (PC) did not result in decrease in the oxidation rate of the NL. Oxidation rate of trilinolein decreased with addition of dipalmitoylphosphatidylethanolamine, while increased with addition of sardine PE. These results show that the PE may act as a synergist on antioxidant effect of alphaーToc on the NL, and that both ethanolamine residue and degree of unsaturation of acyl chains of the PE seem to be involved in the synergist effect of the phospholipids. In the course of this study, sardine TL was found to decrease in oxidation rate after heating at 100^ﾟC for 15-30 min in nitrogen stream. The decrease in oxidation rate of sardine NL occurred, when the NL was mixed with PL and then heated. However, the oxidation rate of sardine NL remained unchanged, when NL and PL were heated separately and then both of the lipids were mixed. The PE was involved in the increased oxidative stability of NL due to heat treatment, while PC and alpha-Toc did not influence oxidation rate of the NL. During heat treatment, the NL interact with PE to form some antioxidative components or to be derived to some stable forms for oxidation.