Fat globules selected from whole milk according to their size: Different compositions and structure of the biomembrane, revealing sphingomyelin-rich domains
Fat globules selected from whole milk according to their size: Different compositions and structure of the biomembrane, revealing sphingomyelin-rich domains
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DOI：
10.1016/j.foodchem.2010.09.005
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发表时间：
2011-03-15
期刊：
影响因子：
8.8
通讯作者：
Robert, Benoit
中科院分区：
文献类型：
--
作者：
Lopez, Christelle;Briard-Bion, Valerie;Robert, Benoit
乳脂球是胃肠道中生物活性分子的独特递送系统。然而，它们的性质尚未得到充分研究。在这项研究中，我们进行了比较分析的极性脂质和脂肪酸组成的乳脂球作为其大小的函数，并研究了乳脂球膜（MFGM）的结构。微滤的优化过程用于从相同的初始全脂乳（4.2 μ m）中选择小乳脂球（SMFG; 1.6 μ m）级分和大乳脂球（LMFG; 6.6 μ m）级分。SMFG级分含有显著（i）较高量的极性脂质，LMFG级分为8.9 +/- 0.9 vs 2.7 +/- 0.3 mg/g脂肪，全脂乳为6.3 +/- 0.5 mg/g脂肪，（ii）MFGM中磷脂酰胆碱和鞘磷脂的相对比例较低，（iii）较高量的C12：0、C14：0、C16：0、C18：1反式、C18：2 c9 tr 11和较低量的C18：0和C18：1c 9比LMFG-级分和全脂乳。无论天然乳脂肪球的大小，生物物理特性进行原位，使用共聚焦激光扫描显微镜，显示在MFGM的异质性。揭示了鞘磷脂在刚性液体有序结构域中的横向分离，所述刚性液体有序结构域被液体无序相中的甘油磷脂的流体基质包围。糖脂和糖蛋白在MFGM中的分布也不均匀。提出并讨论了MFGM结构的新模型。物理，化学和生物学后果，（i）根据其大小的乳脂球组成的差异和（ii）由于鞘磷脂的MFGM的特定结构仍有待阐明。(C)2010爱思唯尔有限公司版权所有。
Milk fat globules are unique delivery systems for biologically active molecules in the gastrointestinal tract. However, their properties have not yet been fully investigated. In this study, we performed a comparative analysis of the polar lipid and fatty acid compositions of milk fat globules as a function of their size and investigated the structure of the milk fat globule membrane (MFGM). An optimised process of microfiltration was used to select the small milk fat globule (SMFG; 1.6 mu m) fractions and the large milk fat globule (LMFG; 6.6 mu m) fractions from the same initial whole milks (4.2 mu m). The SMFG-fractions contained significantly (i) higher amounts of polar lipids, 8.9 +/- 0.9 vs 2.7 +/- 0.3 mg/g fat for LMFG-fractions and 6.3 +/- 0.5 mg/g fat for whole milks, (ii) lower relative proportions of phosphatidylcholine and sphingomyelin in the MFGM, (iii) higher amounts of C12:0, C14:0, C16:0, C18:1 trans, C18:2 c9 tr11, and lower amounts of C18:0 and C18:1 c9 than did LMFG-fractions and whole milks. Whatever the size of native milk fat globules, the biophysical characterisation performed in-situ, using confocal laser scanning microscopy, showed heterogeneities in the MFGM. The lateral segregation of sphingomyelin in rigid liquid-ordered domains, surrounded by the fluid matrix of glycerophospholipids in the liquid-disordered phase, was revealed. The heterogeneous distribution of glycolipids and glycoproteins was also observed in the MFGM. A new model for the structure of the MFGM is proposed and discussed. The physical, chemical and biological consequences, (i) of the differences in milk fat globule compositions according to their size and (ii) of the specific structure of the MFGM due to sphingomyelin remain to be elucidated. (C) 2010 Elsevier Ltd All rights reserved.