Changes of Lipid and Fatty Acid Composition in Shrimps (Litopenaeus vannamei) before and after Hot-air-drying

To study the changes of lipid and fatty acid composition of shrimps (Litopenaeus vannamei) before and after hot-air-dried, lipid components were separated by silica gel column chromatography and the fatty acid composition of total lipids, triglyceride, phosphatidylethanolamine and phosphatidylcholine was determined by gas chromatography-mass spectrometry (GC-MS). The results showed that after dried, the total lipid content of shrimps decreased extremely significantly (P<0.01), from 6.46 g/100 g (dry weight) to 4.28 g/100 g, and the contents of triglyceride, phosphatidylethanolamine and phosphatidylcholine decreased by 28.4%, 34.1% and 37.9%, respectively. However, the changes of other lipid components were little. After dried, the total fatty acid content of shrimps decreased from 1368.53 mg/100 g to 1143.60 mg/100 g, and the most reduced fatty acids were C16:0, C18:1, C18:2 and C18:3. Total fatty acid content of triglycerides decreased by 68.25%, which C16:0, C18:1 and C18:2 decreased by 82.06%, 86.07% and 80.83%, respectively. Total fatty acid content of phosphatidylethanolamine decreased by 47.92%, which C16:0, C18:0, C18:1, C18:2, C20:5 and C22:6 decreased by 50.27%, 41.80%, 68.72%, 52.91%, 39.63% and 53.76%, respectively. The total fatty acid content of phosphatidylcholine decreased by 19.5%, which C18:1 and C18:2 decreased by 35.85% and 34.12%, respectively. Lipid is the main precursor of characteristic aroma of dried shrimp products, the study of the changes of lipid and fatty acid composition will provide a reference for analyzed the mechanism of lipid thermal degradation and formation of the characteristic aroma of dried shrimp products.