即食虾干加工过程脂质变化研究

Changes in lipids of dried shrimp products during processing

摘要:

为探究即食虾干加工过程中脂质的变化情况，以凡纳滨对虾（Litopenaeus vannamei）为研究对象，分别取鲜虾、煮虾、干燥2 h、干燥4 h的样品，对总脂含量、脂质组成、脂肪酸组成、酸价（acid value，AV）、过氧化值（peroxide value，POV）、硫代巴比妥酸反应值（thiobarbituric acid reactive substances，TBARS）进行了检测分析。结果表明，鲜虾总脂含量为8.74 g/100 g（干基计），在煮制和干制过程中变化不显著（P>0.05）。脂质组成发生明显变化，煮后甘油三酯和游离脂肪酸的比例显著降低（P<0.05），而磷脂比例显著升高（P<0.05）。在干制过程中，磷脂比例呈下降趋势，游离脂肪酸比例呈上升趋势，而胆固醇比例相对稳定。脂肪酸组成在加工过程总体变化较小，其中多不饱和脂肪酸在干制阶段含量有所减少，相对地提高了饱和脂肪酸含量。虾干加工过程中，POV呈先上升后下降的变化趋势，AV在煮后急剧下降，而干制后增加，TBARS一直上升。因此，虾干加工过程中煮制和热风干燥会影响脂质组分的比例，同时引起脂质的氧化分解。为即食虾干加工工艺的优化、品质控制及风味形成提供理论参考。

Abstract:

In order to explore the change of lipids in the drying process of ready-to-eat shrimp, the samples of fresh shrimp, cooked, dried for 2 h and dried for 4 h were taken respectively, and the total fat content, lipid composition, fatty acid composition, acid value(AV), peroxide value (POV), thiobarbiturate acid reacting substances(TBARS) were analysed. The results showed that the total fat content of fresh shrimp was 8.74 g/100 g (on dry basis), which did not change significantly during cooking and drying (P>0.05).There was a significant change in lipid composition, with a significant decrease in the ratio of triglycerides and free fatty acids after cooking (P<0.05), while the proportion of phospholipids increased significantly (P<0.05).In the drying process, the proportion of phospholipids showed a downward trend, the proportion of free fatty acids showed an upward trend, while the proportion of cholesterol was relatively stable. The composition of fatty acids changed less in the process, in which the content of polyunsaturated fatty acids decreased in the drying stage and the content of saturated fatty acids was increased relatively. During shrimp drying processing, POV shows a trend of first rising and then decreasing, while AV decreases sharply after cooking, while increases after drying and TBARS continues to rise. Thus, cooking and hot air drying during shrimp drying will affect the proportion of lipid components, and cause the oxidation and decomposition of lipids. The theoretical reference is provided for the optimization, quality control and flavor formation of ready-to-eat shrimp drying process.