13C核磁共振技术测定鱼肝油中ω-3脂肪酸α(1,3)-酰基和β(2)-酰基的位次分布

Position Distribution Study of α(1,3)-acyl and β(2)-acyl of ω-3 Fatty Acids in Cod Liver Oil by 13C-NMR

关键词:  ¹³C核磁共振  ω-3脂肪酸  α(1,3)-酰基  β(2)-酰基  位次分布

Key words:  ¹³C-NMR  ω-3 fatty acids  α(1,3)-acyl  β(2)-acyl  position distribution

摘要:

目的 应用¹³C核磁共振（¹³C-NMR）光谱测定鱼肝油中ω-3脂肪酸[十八碳四烯酸（C18：4 n-3，moroctic acid，MA）、二十碳五烯酸（C20：5 n-3，eicosapentaenoic acid，EPA）、二十二碳六烯酸（C22：6 n-3，docosahexaenoic acid，DHA）]形成的甘油三脂中α（1，3）-酰基、β（2）-酰基的位次分布。方法 用CDCl₃溶解样品，利用高分辨核磁共振光谱直接测定。结果 鱼肝油中MA、EPA和DHA α（1，3）-酰基、β（2）-酰基在δ 171.5~173.5 ppm的化学位移与文献报道基本一致。2批次鱼肝油未发现上述ω-3脂肪酸特征峰，4批次鱼肝油有特征峰检出，但是β（2）-酰基的位次分布不同。按照β（2）-酰基的比例，4批鱼肝油来源于家养鱼类提取的可能性较大。结论 应用该¹³C核磁共振技术可以鉴别鱼肝油的优劣，方法简单、快捷。

Abstract:

OBJECTIVE The position distribution α (1,3)-acyl and β(2)-acyl of ω-3 fatty acids[moroctic acid (C18:4 n-3, MA), eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid(C22:6 n-3, DHA)] in the form of triacylglycerols in cod liver oil have been examined by ¹³C-NMR. METHODS The samples were directly determinated with dissolving in CDCl₃ by high resolution ¹³C-NMR spectroscopy. RESULTS The ¹³C NMR-derived data of the position distribution α(1,3)-acyl and β(2)-acyl for MA, EPA and DHA in δ 171.5-173.5 ppm were consistented with corresponding data reported in the literature. The characteristic peaks of ω-3 fatty acids in two batches cod liver oil were not detected, but that were measured in four batches of cod liver oil with different the position distribution[β(2)-acyl]. According the ratio of the position distribution[β(2)-acyl], the more possibility of extracting from farmed fish in four batches of cod liver oil was found. CONCLUSION The method of ¹³C-NMR is simple and quick, which can identify good or bad quality of cod liver oil.