Jensen R G, Ferris A M, Lammi-Keefe C J, Henderson R A
Department of Nutritional Sciences, University of Connecticut, Storrs 06269-4017.
J Dairy Sci. 1990 Feb;73(2):223-40. doi: 10.3168/jds.S0022-0302(90)78666-3.
Human and bovine milks contain about 3 to 5% total lipid, existing as emulsified globules 2 to 4 microns in diameter and coated with a membrane derived from the secreting cell. About 98% or more of the lipid is triacylglycerol, which is found in the globule. Phospholipids are about .5 to 1% of total lipids and sterols are .2 to .5%; these are mostly located in the globule membrane. Cholesterol is the major sterol. The major differences are in fatty acid composition, triacylglycerol structure, and the response of fatty acids in human milk to changes in diet. Bovine milk contains substantial quantities of 4:0 to 10:0, about 2% 18:2, and almost no other long-chain polyunsaturated fatty acids. The fatty acid composition is not altered by ordinary changes in diet. Human milk contains very little 4:0 to 10:0, 10 to 14% 18:2, and small quantities of other polyunsaturates. The triacylglycerol structure differs, with much of the sn-2 position occupied by 16:0 in human milk and 4:0 to 10:0 at sn-3 in bovine milk. The effects of milk cholesterol and fatty acids on human blood cholesterol levels are discussed.
人乳和牛乳中的总脂质含量约为3%至5%，以直径为2至4微米的乳化小球形式存在，并包裹着一层源自分泌细胞的膜。脂质中约98%或更多是三酰甘油，存在于小球中。磷脂约占总脂质的0.5%至1%，固醇占0.2%至0.5%；它们大多位于小球膜中。胆固醇是主要的固醇。主要差异在于脂肪酸组成、三酰甘油结构以及人乳中脂肪酸对饮食变化的反应。牛乳含有大量的4:0至10:0脂肪酸，约2%的18:2脂肪酸，几乎不含其他长链多不饱和脂肪酸。普通饮食变化不会改变其脂肪酸组成。人乳中4:0至10:0脂肪酸含量极少，18:2脂肪酸含量为10%至14%，还有少量其他多不饱和脂肪酸。三酰甘油结构有所不同，人乳中sn-2位大多被16:0占据，而牛乳中sn-3位为4:0至10:0。本文还讨论了乳中的胆固醇和脂肪酸对人体血液胆固醇水平的影响。
