草鱼片热风干制过程中脂质氧化特性研究

探讨热风干燥过程中青鱼片油脂的变化情况。在青鱼片的不同干燥阶段提取油脂,检测油脂氧化程度,油脂成分及脂肪酸组成的含量变化。在干燥过程中鱼片油脂的过氧化值、羰基价和酸价显著性升高(P<0.05)。随着甘油三酯和磷脂含量的下降,游离脂肪酸含量明显增加,表明在干制过程中油脂在酯酶和磷酸化酶的催化下发生了水解反应。在总油脂和总磷脂中多不饱和脂肪酸,尤其是二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量下降。在游离脂肪酸中,除DHA以外的多不饱和脂肪酸含量均显著升高。研究结果表明,青鱼片热风干燥过程中其油脂被氧化,同时发生脂质降解,特别是不饱和脂肪酸被释放为游离态。

Research on Lipid Oxidation during Heat-drying of Grass Carp (Ctenopharyngodon idellus) Fillets

Changes in lipids of grass carp fillets during heat-drying were investigated.Lipid was extracted from grass carp fillets following different drying stages to measure the degree of lipid oxidation.Changes in lipid composition and fatty acid profile were also detected.Peroxide value,carbonyl value and acid value of the lipids were significantly increased(p<0.05) during the drying period.Marked increase in free fatty acids,with decreases in triglyceride and phospholipids content were observed in proportion to drying time and this result suggested that hydrolysis was induced by lipases and phospholipases.The decreases in polyunsaturated fatty acids(PUFAs),especially eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA),were observed in the total lipids and phospholipids fraction.In addition,significant increase in PUFAs especially DHA was found in the free fatty acid fraction.These results suggested that during drying period lipid oxidation was not only occurred but also lipolysis predominantly released polyunsaturated fatty acids.