亚麻酸甘油酯异构体形成动力学及不同酰化位置对热致异构体差异比较

Formation Kinetics of Glyceryl Linolenate Isomers and Comparison of Different Acylation Positions on Thermotropic Isomers

摘要:

研究亚麻酸甘油三酯在加热时反式亚麻酸形成的动力学的差异以及亚麻酸在甘油酯不同酰化位置对热致异构反式产物种类影响。采用GC-FID 分析亚麻酸反式异构体，发现亚麻酸甘油三酯中有7种反式异构体生成，亚麻籽油有6种反式异构体生成，该反应为零级反应。对比亚麻酸甘油三酯和亚麻籽油的动力学参数：在亚麻酸甘油三酯和亚麻籽油中，C18:3-9t,12c,15c、C18:3-9c,12t,15c和C18:3-9c,12c,15t形成的活化能分别为79.39、106.49、82.33 kJ/mol和86.04、115.84、102.85 kJ/mol；C18:3-9t,12c,15t和C18:3-9t,12t,15c分别为180.57、233.55 kJ/mol和164.36、165.38 kJ/mol；C18:3-9t,12t,15t分别为211.79 kJ/mol和140.30 kJ/mol。对比monolinolenin、dilinolenin、1,3-dilinolenin的异构体种类含量可知，Sn-1和2位比Sn-1和3位更稳定；Sn-1位比Sn-1和3位还有Sn-1和2位更稳定。因此，亚麻酸甘油三酯基本比亚麻籽油跨越的能垒高；对于酰化位置，Sn-1和2位比Sn-1和3位更稳定，Sn-1位比Sn-1和3位还有Sn-1和2位更稳定。

Abstract:

The differences in the formation kinetics of trans linolenic acid in linolenic acid triglycerides during heating and the effects of linolenic acid at different acylation positions in the glycerides on the types of thermally isomerized trans products were studied. Using GC-FID to analyze the trans isomers of linolenic acid, it was found that there were 7 trans isomers in the linolenic acid triglyceride and 6 trans isomers in linseed oil, and the reaction was zero-order. The kinetic parameters of linolenic acid triglyceride and linseed oil were compared, and it was found that in linolenic acid triglyceride and linseed oil, the activation energies of C18:3-9t,12c,15c, C18:3-9c,12t,15c and C18:3-9c,12c,15t were 79.39, 106.49 and 82.33 kJ/mol, and 86.04, 115.84 and 102.85 kJ/mol, respectively; the activation energies of C18:3-9t,2c,15t and C18:3-9t,12t,15c were 180.57 and 233.55 kJ/mol, and 164.36 and 165.38 kJ/mol, respectively; the activation energies of C18:3-9t,12t,15t were 211.79 and 140.30 kJ/mol, respectively. With the comparison on the the isomer contents of monolinolenin, dilinolein and 1,3-dilinolenin revealed that Sn-1 and Sn-2 were more stable than Sn-1 and Sn-3; Sn-1 was more stable than Sn-1 and Sn-3, and Sn-1 and Sn-2. Therefore, the energy barrier of linolenic acid triglyceride was basically higher than that of linseed oil; In terms of acylation sites, Sn-1 and Sn-2 was more stable than Sn-1 and Sn-3, and Sn-1 was more stable than Sn-1 and Sn-3, and Sn-1 and Sn-2.