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

采用SS-10型毛细管色谱柱，建立了测定脂肪酸几何异构体的气-液色谱方法。GC-MS方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，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。供机构使用的氢化产品含有很高比例的反式异构体。反式十八碳烯酸酯略微改变了大鼠肠道菌群的组成，促进了胆固醇向辅酶前体的转化，这可能归因于酶活性的变化。反式脂肪酸作为一种能源的利用与顺式脂肪酸一样有效。反式异构体在大鼠组织中无特异性沉积，停止摄取后迅速消失。氢化海油中的反式二十碳烯酸酯和十二碳烯酸酯在大鼠组织中不沉积。反式脂肪酸减少了大鼠心脏线粒体磷脂中多不饱和脂肪酸的比例，并在亚油酸供应不足的情况下抑制了呼吸活动。反式脂肪酸没有刺激小鼠胆固醇结石的形成，也降低了仓鼠的致石指数。在各种动物中，反式脂肪酸降低了血浆中的胆固醇水平，而且在禽类中，氢化脂肪的致动脉粥样硬化活性低于非氢化脂肪。尽管反式脂肪酸抑制了大鼠的血小板聚集，但主要二十烷类化合物的产生保持不变。反式脂肪酸既不促进致癌物诱导的大鼠乳腺肿瘤，也不促进大鼠的结肠癌。

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.