Nutritional and Physiological Assessment of trans-Monoene Fatty Acids in Hydrogenated Fat Products

采用SS-10毛细管柱建立了测定脂肪酸几何异构体的气液色谱方法。发现气相色谱-质谱法可用于位置异构体的快速分析。家用人造黄油中反式脂肪酸的原型是反式十八烯酸酯，平均占总脂肪酸的10%，只有少量的多不饱和脂肪酸异构体出现。机构使用的氢化产品含有高比例的反式异构体。反式十八烯酸酯轻微地改变了大鼠肠道菌群的构成，并且胆固醇转化为辅助衍生物的增强可能归因于酶活性的改变。反式脂肪酸与顺式脂肪酸一样被有效地用作能量来源。反式异构体在大鼠组织中没有特异性沉积，并且在停止摄入后迅速消失。氢化海洋油中的反式二十焦糖酸酯和二十焦糖酸酯在大鼠组织中没有沉积。当亚油酸供应不足时，反式脂肪酸降低了大鼠心脏线粒体磷脂中多不饱和脂肪酸的比例，抑制了呼吸活动。反式脂肪酸不会刺激小鼠胆固醇胆石的形成，也会降低仓鼠的产石指数。在各种动物中，反式脂肪酸降低了血浆胆固醇水平，在鹌鹑中，氢化脂肪的致动脉粥样硬化活性低于未氢化脂肪。虽然反式脂肪酸抑制大鼠血小板聚集，但主要类二十烷酸的产生保持不变。反式脂肪酸对致癌物质诱导的大鼠乳腺肿瘤和结肠肿瘤均无促进作用。

A gas-liquid chromatographic method for determination of geometrical isomers of fatty acids was developed using a SS-10 capillary column. The GC-MS method was found to be useful for the rapid analysis of positional isomers. The prototype of trans-fatty acids in home-use margarines was trans-octadecenoates comprising on the average 10% of total fatty acids and only negligible amounts of the polyunsaturated fatty acid isomers occurred. Hydrogenated products for institutional use contained a high proportion of trans-isomers. Trans-octadecenoates slightly modified the constitution of intestinal microflora of rats, and an enhanced conversion of cholesterol to coproderivatives could be attributed to the change in enzymatic activity. Trans-fatty acids were utilized as an energy source as effectively as the cis-counterparts. There was no specific deposition of trans-isomers in rat tissues and they rapidly disappeared on discontinuance of ingestion. Trans-eicosenoates and dococenoates in hydrogenated marine oil did not deposite in rat tissues. Trans-fatty acids reduced the proportion of polyunsaturated fatty acids in rat heart mitochondrial phospholipids and depressed respiratory activity when the supply of linoleic acid was marginal. Trans-fatty acids did not stimulate the formation of cholesterol gallstone in mice and also reduced a lithogenic index in hamsters. In various animals, trans-fatty acids reduced plasma cholesterol levels and the atherogenic activity in quails was lower in hydrogenated fat than in unhydrogenated fats. Although trans-fatty acids depressed platelet aggregation in rats, the production of major eicosanoids remained unchanged. Trans-fatty acid promoted neither carcinogen-induced mammary tumors nor colon tumors in rats.