乳脂肪球膜(MFGM)的组成及生理特性

综述了MFGM的组成、结构、MFGM的分离纯化,并对MFGM对人类具有有益生理效应的组分进行了总结,为今后MFGM的研究开发和更广泛的应用提供了一定的应用参考.     

乳脂肪球膜制备方法及其乳化特性的研究进展

乳脂肪球膜是包裹在乳脂肪球外层的复杂三层膜结构,主要成分为蛋白质和脂质.近年来研究表明乳脂肪球膜具有亲水亲油性,能有效地阻止乳脂肪球之间的聚集,是一种性能良好的天然乳化剂.该文主要介绍了工业规模制备乳脂肪球膜原料来源、制备方法和影响条件及乳脂肪球膜良好的乳化特性,并对其潜在工业应用进行了详细综述,旨在为乳脂肪球膜的进一...     

乳脂肪球膜的组成与应用研究进展

综述了乳脂肪球膜的组成、分离提取方法与应用的研究进展,对有效利用乳脂肪球膜资源提供参考。     

乳脂肪球膜改善肠道微生物的研究进展

具有多种生理功能的乳脂肪球膜（MFGM）是婴儿配方奶粉的重要原料,MFGM具有支持大脑发育、防止病原体黏附肠道上皮细胞、提高宿主的免疫力等功能。另外,MFGM和人乳菌群积极与肠道黏膜屏障合作,对建立健康婴儿肠道菌群发挥重要作用。文章综述了MFGM的组成、在婴儿配方奶粉中的作用、及对肠道微生物的影响。总结了近几年研究人员利用临床研究、动物实验和体外模拟研究MFGM影响肠道微生物方面取得的成果,并提出未来MFGM在调节肠道微生物方面的研究建议。     

乳脂肪球膜的组成、营养及制备研究进展

乳中的脂肪以乳化的脂肪球形态分散于水相中,脂肪球被三层脂肪球膜包裹,近年来的研究表明脂肪球膜中的成分对婴幼儿的生长发育有至关重要的作用。本文介绍了乳脂肪球膜特别是其磷脂的组成及含量,添加入婴幼儿配方奶粉中乳脂肪球膜的营养作用,以及目前市售的富含脂肪球膜的产品及制备方式,为缩小配方奶与婴幼儿营养需求的差异提供科学依据。     

乳脂消化吸收及其功能研究进展

乳脂肪球是由甘油三酯为核心的小球组成,周围有三膜结构,即乳脂肪球膜。乳脂肪球膜含有复杂的脂质和蛋白质,具有营养、免疫、神经和消化功能。然而,这些功能和胃肠消化之间存在的联系及其影响乳脂胃肠消化的因素未得到充分的研究。文章综述了乳脂成分及其结构、乳脂功能特性、乳脂胃肠消化概况及其影响乳脂消化吸收的因素,旨在为婴儿配方奶粉的消化研究提供参考。     

乳脂肪球膜在不同人群中的临床研究进展

乳脂肪球膜（MFGM）含有多种功能性蛋白和极性脂质,对人体健康可以产生重要的积极影响,如减少肠道疾病、有助于大脑发育、提高免疫、调节代谢、改善身体机能和运动能力等。文章按照婴幼儿、儿童、成人、老年人4个年龄段人群,综述了MFGM在不同人群中生理作用的临床研究及安全性评价,旨在为MFGM的相关研究及其产品的开发利用提供参考。     

不同乳源乳脂肪球的体外消化特性

基于模拟婴幼儿胃肠道消化,采用粒径分布、Zeta电势和激光共聚焦扫描电镜观察不同乳源(牛、羊、驼)乳脂肪球(MFG)在消化各阶段物理特性的差异,采用气相色谱-质谱联用及滴定法,探究在不同消化阶段游离脂肪酸及脂解速率的变化,完善脂质消化的变化规律。结果表明,不同乳源MFG的颗粒粒径随消化时间的延长,均呈减小的趋势,与激光共聚焦显微镜染色后观察结果一致。在肠消化末端,驼乳MFG的平均粒径为(0.46±0.07)μm,显著低于牛乳MFG的粒径(P<0.05)。动态光散射电位仪测得电势绝对值显示,所有乳源MFG进胃肠消化后均表现出强负电性,其中肠消化末端的电位绝对值由大至小排序为羊乳>牛乳>驼乳。不同乳源MFG在肠道消化期间的脂解速率无明显差异,而驼乳MFG相较于其它两种乳源在不同消化阶段,棕榈油酸(C16 ∶ 0)的含量显著更高(P<0.05),长链脂肪酸比例更低。研究结果为驼乳产品的加工以及新型配方奶粉的制备提供新思路。     

乳脂肪球膜蛋白组成及其功能特性

本文介绍了MFGM的组成和结构,通过对比牛乳、羊乳以及骆驼乳等5种乳源MFGM组成,解析了不同乳源MFGM的组成、结构及含量差异。从蛋白质组学角度综述了牛乳、羊乳以及骆驼乳等不同乳源MFGM蛋白的组成成分及其含量差异,并阐述了不同乳源MFGM蛋白与人乳之间的相似性。筛选并系统地阐述了高丰度和高表达差异MFGM蛋白在乳化性和稳定性、消化稳定性以及对人体的安全性和耐受性方面的作用。综述了MFGM蛋白在抗癌、增强免疫力、修复肠道损伤、改善血脂、抗少肌症以及促进神经系统发育和提高认知能力过程中所参与的代谢途径和作用机制,为开发与利用MFGM蛋白提供了参考依据。     

乳脂肪球及其微观结构

乳是哺乳动物的乳腺所分泌的具有胶体特性的生物化学液体。乳脂肪从脂肪球状态分散在乳浆中,为“油在水中”的乳浆液。新挤出的牛乳是两相乳浊液。乳在长时间保持冷却状态后,乳脂肪球中脂肪部分结晶化并形成三相或多相乳浊液。在电子显微镜下,最完整的乳成分结构是脂肪球。     

Changes in the surface protein of the fat globules during ultra-high pressure homogenisation and conventional treatments of milk

Disruption of fat globules upon homogenisation provokes a reduction of their size and a concomitant increase in their specific surface area. In order to overcome this phenomenon, the milk fat globule membrane (MFGM) adsorbs non-native MFGM proteins. The aim of the present study was to examine the effects of UHPH conditions (temperature and pressure) on the milk fat globule and the surface proteins by comparison with conventional treatments applied in the dairy industry. Transmission electron microscopy and SDS-PAGE revealed major differences. In UHPH-treated milk, casein micelles were found to be adsorbed on the MFGM in a lesser extent than in conventional homogenisation–pasteurisation. However, greater adsorption of directly bonded casein molecules, released by UHPH through the partial disruption of casein micelles, was observed especially at high UHPH pressures. Adsorption of whey proteins on the MFGM of conventionally homogenised–pasteurised milk was mainly through intermolecular disulfide bonds with MFGM material, whereas in UHPH-treated milk, disulfide bonding with both indirectly and directly adsorbed caseins was also involved.     

Effect of nonthermal technologies on the native size distribution of fat globules in bovine cheese-making milk

Milk-fat globule membranes are susceptible to damage by mechanical and thermal processes. This damage is translated into alterations of milk fat structure and functionality of cheese-making milk. The objective of this work was to evaluate the effect of pulsed electrical fields (PEF), high hydrostatic pressure (HHP), and conventional thermal treatments on fat globule size distribution and ζ-potential. Milk was processed by HHP at 400 and 500 MPa for 0–20 min, and with PEF at 36 kV/cm and 42 kV/cm up to 64 pulses. The ζ-potential of HHP and PEF treated milk were − 15.47 mV and − 14.63 mV respectively. HHP treatments induced fat globules flocculation, increasing their mass moment mean diameter. Although PEF processing did not modify the true mean diameter of MFG, it induced small globules to clump together, causing an apparent increment in the population of larger milk-fat globules.

Industrial relevance

The market for traditional raw dairy products has increased in recent times in several regions of the world due to their unique flavor and texture attributes. However, the potential negative implications of consuming raw products limit the growth of this market segment. Manufacture of raw-like cheese from thermally pasteurized milk is not feasible, among other things, because of milk fat globule membrane damage caused by elevated temperatures. Nonthermal food preservation technologies offer the potential to produce milk technically suitable for the industrial manufacture of microbiologically safe raw-like dairy products.     

Milk fat globule membrane – a source of polar lipids for colon health? A review

The milk fat globule membrane (MFGM) surrounds fat globules, protects them against lipolysis and disperses the milk fat in the milk plasma. Besides their structural and emulsifying roles, in vivo and in vitro studies have demonstrated that phospholipids and sphingolipids of MFGM possess cancer risk‐reducing properties. Several reports attribute its chemopreventive activity to products of sphingomyelin hydrolysis, which affect multiple cellular targets that control cell growth, differentiation and apoptosis. With knowledge on the potential health benefits of MFGM lipids and proteins, dairy industries could in the future address their research in developing new functional dairy products enriched in beneficial MFGM components.     

Milk fat globule membrane glycoproteins: Valuable ingredients for lactic acid bacteria encapsulation?

The membrane (Milk Fat Globule Membrane – MFGM) surrounding the milk fat globule is becoming increasingly studied for its use in food applications due to proven nutritional and technological properties. This review focuses first on current researches which have been led on the MFGM structure and composition and also on laboratory and industrial purification and isolation methods developed in the last few years. The nutritional, health benefits and techno-functional properties of the MFGM are then discussed. Finally, new techno-functional opportunities of MFGM glycoproteins as a possible ingredient for Lactic Acid Bacteria (LAB) encapsulation are detailed. The ability of MFGM to form liposomes entrapping bioactive compounds has been already demonstrated. One drawback is that liposomes are too small to be used for bacteria encapsulation. For the first time, this review points out the numerous advantages to use MFGM glycoproteins as a protecting, encapsulating matrix for bacteria and especially for LAB.     

Fat globules selected from whole milk according to their size: Different compositions and structure of the biomembrane,revealing sphingomyelin-rich domains

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 μm) fractions and the large milk fat globule (LMFG; 6.6 μm) fractions from the same initial whole milks (4.2 μm). 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.     

Milk fat globule membrane proteins are involved in controlling the size of milk fat globules during conjugated linoleic acid–induced milk fat depression

Milk fat globule membrane (MFGM) proteins surround the triacylglycerol core comprising milk fat globules (MFG). We previously detected a decrease in the size of fat globules during conjugated linoleic acid (CLA)-induced milk fat depression (MFD), and other studies have reported that some MFGM proteins play a central role in regulating mammary cellular lipid droplet size. However, little is known about the relationship between MFD, MFG size, and MFGM proteins in bovine milk. The aim of this study was to investigate the profile of MFGM proteins during MFD induced by CLA. Sixteen mid-lactating Holstein cows (145 ± 24 d in milk) with similar body condition and parity were divided into control and CLA groups over a 10-d period. Cows were fed a basal diet (control, n = 8) or control plus 15 g/kg of dry matter (DM) CLA (n = 8) to induce MFD. Cow performance, milk composition, and MFG size were measured daily. On d 10, MFGM proteins were extracted and identified by quantitative proteomic analysis, and western blotting was used to verify a subset of the identified MFGM proteins. Compared with controls, supplemental CLA did not affect milk production, DM intake, or milk protein and lactose contents. However, CLA reduced milk fat content (3.73 g/100 mL vs. 2.47 g/100 mL) and the size parameters volume-related diameter D_[4,3] (3.72 μm vs. 3.35 μm) and surface area-related diameter D_[3,2] (3.13 μm vs. 2.80 μm), but increased specific surface area of MFG (1,905 m²/kg vs. 2,188 m²/kg). In total, 177 differentially expressed proteins were detected in milk from cows with CLA-induced MFD, 60 of which were upregulated and 117 downregulated. Correlation analysis showed that MFG size was negatively correlated with various proteins, including XDH and FABP3, and positively correlated with MFG-E8, RAB19, and APOA1. The results provide evidence for an important role of MFGM proteins in regulating MFG diameter, and they facilitate a mechanistic understanding of diet-induced MFD.