The Degradation Of Phospholipids In Sea Urchin During Cold Storage

Sea urchin gonad as the only edible part of sea urchin,it is rich in nutrients and phospholipids.Due to the high content of polyunsaturated fatty acids in phospholipids,lipid hydrolysis and oxidation reactions may happen during storage and transportation,which affects the quality and flavor of sea urchin.In this study,degradation of phospholipids in sea urchin was studied during 4 ? storage.The study results are as follows:1.Total lipid was extracted by chloroform and menthanol.The lipid composition of sea urchin gonad was analyzed by column chromatography.It was found that the phospholipids content decreased from 46% to 29% with the storage time.The results showed that hydrolysis and oxidation of phospholipids were found in sea gonads urchins during storage.The composition of phospholipids was measured by evaporative light scattering detector.The results showed that sea urchin gonad mainly contained phosphatidylethanolamine,phosphatidylcholine and phosphatidylinosidol,during storage at 4?,the content of phosphatidylethanolamine and phosphatidylinosidol decreased gradually,while the content of PC increased first and then declined,and LPC appeared after 48 h,which was supposed from PC degradation.The results showed that hydrolysis and oxidation of phospholipids were found in sea gonads urchins during storage.2.The fatty acid composition of total lipid/phospholipids was measured by gas chromatographic.It was found that more than 20 kinds of fatty acids contained in the phospholipids,mainly contained C16:0?C20:4n6?C20:2?C20:5n3?C20:2,and the ratio of unsaturated fatty acids / saturated fatty acids gradually decreased from 5.33% to 4.33% during storage.The results showed that the fatty acids of phospholipids in sea urchin were oxidized.The content of oxidation reaction products were measured,it was found that POV increased first and then decreased,while TBARS showed an upward trend.It was proved that sea urchin gonad was oxidized during storage.3.Sea urchin gonads were treated with antioxidant(VE)and phospholipase D inhibitor(n-butanol).The activity of the enzyme was significantly decreased after the addition of the n-butanol.It was found that the contents of PE?PC and PI in sea urchin gonads did not change much,however,the content of LPC decreased after the addition of n-butanol,and it was speculated that the n-butanol inhibited PC hydrolysis.The content of choline of sea urchin gonads was not changed during storage,and the content of choline in the phospholipid was higher than that in the group without n-butanol.The n-butanol inhibits the activity of phospholipase D,by which degradation of PC reduced.4.After adding inhibitor of lipoxygenase(VE),the lipase activity decreased significantly,and the contents of POV and TBARS showed a downward trend,which indicated that VE can inhibit the oxidation degree of sea urchin gland.It was showed that VE can effectively inhibit the degradation of PE and PI;while PC also showed a decrease in the storage process,and LPC appeared after 48 h,its content was lower than without VE,indicating that VE inhibits PC hydrolysis and reduces the degradation of LPC content.This result proves that VE can effectively inhibit lipid oxidation and phospholipids in sea urchin gonad.