氢化大豆油和反刍动物油脂中甘油三酯和磷脂反式脂肪酸的位置分布

摘要

以氢化大豆油和反刍动物脂质为研究对象,采用Folch法提取油脂,氨丙基硅胶固相萃取小柱分离出油脂中的甘油三酯和磷脂,利用Sn-1,3专一性脂肪酶作用甘油三酯得到Sn-2甘油一酯和游离脂肪酸,磷脂酶A2作用磷脂得到游离脂肪酸和Sn-1溶血磷脂,并通过气相色谱分析2种不同来源油脂反式脂肪酸在甘油三酯和磷脂中的含量和位置分布情况.结果表明,反式脂肪酸占氢化大豆油甘油三酯总脂肪酸的41.466％,占反刍动物油脂甘油三酯总脂肪酸的2.451％～3.179％.反式脂肪酸在氢化大豆油甘油三酯中主要分布在Sn-2位,而在反刍动物油脂甘油三酯中主要分布在Sn-1,3位,在反刍动物油脂磷脂中则易分布在Sn-1上.不同来源的反式脂肪酸的膳食摄入量及其在甘油三酯中的位置分布不同,可能是导致不同来源反式脂肪酸对人体健康影响差异的原因.%Lipids from partially hydrogenated soybean oil and ruminant animal fat were extracted by the Folch methods,and then separated using a NH2 solid phase extraction (SPE) cartridge to obtain triglycerides and phospholipids.The analyses were carried out after using Sn-l,3-specific lipase to hydrolyze the acyl group Sn-1 and Sn-3 in triglycerides,and using phospholipase A2 to hydrolyze the acyl group at the Sn-2 position of phospholipids,which were finally converted to fatty acid methyl esters and analyzed by gas chromatography.Results showed that trans fatty acids accounted for 41.466％ and 2.451％-3.179％ of the total fatty acids in triglycerides from hydrogenated soybean oil and ruminant animal fat,respectively.Trans fatty acids were selectively located at the Sn-2 position of hydrogenated soybean oil triglycerides and at the Sn-1,3 position of ruminant animal fat triglycerides.For ruminant animal fat phospholipids,trans fatty acids were preferentially located at the Sn-1 position.Dietary intake of trans fatty acids from different sources and their different positional distribution preferences in triglycerides may be the cause of the fact that trans fatty acids from different sources have different impacts on human health.