Intracellular Origin of Milk Fat Globules and the Nature of the Milk Fat Globule Membrane

Keenan, T.W.; Mather, Ian H.

doi:10.1007/0-387-28813-9_4

Cited by 107 publications

(169 citation statements)

References 121 publications

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“…The droplets grow during their migration to the apical pole of the cell due to the continuation of the synthesis of lipids (Ollivier-Bousquet, 2002;Heid and Keenan, 2005;McManaman et al, 2007). The secretion would correspond to the membrane enwrapping the CLD and its secretion in association with the exocytosis of the golgiderived secretory vesicles containing caseins micelles (Wu et al, 2000;Keenan and Mather, 2006;Robenek et al, 2006;McManaman et al, 2007;Truchet et al, 2014). According to Heid and Keenan (2005), these mechanisms should be regulated but the regulation processes remain hypothetic.…”

Section: Introductionmentioning

confidence: 99%

Relationships between milks differentiated on native milk fat globule characteristics and fat, protein and calcium compositions

Couvreur

Hurtaud

2017

Animal

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Many studies have shown that milk fat globule (MFG) diameter varies in dairy cows in relation to diet and/or breed. However, the mechanisms governing the size of the fat globules remain hypothetical. Our objective was to determine the variable biochemical characteristics (fat, protein, fatty acids (FA), casein and calcium (Ca) contents) between individual milk which differed in both MFG diameter and membrane content, in order to speculate about the links between milk synthesis and MFG secretion. With this aim, we built five databases of individual milk samples from 21 experiments performed between 2003 and 2011. Three of them grouped data from trials dealing with breed/diet effects and included information about: (i) MFG size/membrane, fat and protein contents (n = 982), (ii) previous parameters plus FA profile (n = 529) and (iii) previous parameters plus true protein composition and calcium contents (n = 101). A hierarchical clustering analysis performed on these three databases yielded four groups differing in the MFG characteristics. We observed significant differences among groups for the following parameters: (i) fat content and fat : protein ratio; (ii) de novo and polyunsaturated FA contents; (iii) Ca contents. These relationships could result from potential process regulating the synthesis and secretion of MFG: (i) the apical membrane turnover for MFG secretion and (ii) cytoplasmic lipid droplet formation in the lactocyte during its migration from the basal to the apical pole. The two other databases grouped data from trials dealing with milking frequency (n = 211), milking kinetics and milk type (residual v. cisternal) (n = 224). They were used to study the relationships between the size of the MFG and milk composition for high native fat contents (from 60 up to 100 g/kg in residual milks). We observed curvilinear relationships between the size of the MFG and fat content, as well as with the fat : protein ratio. This result suggests that MFG diameter reaches a threshold but mechanisms are still unknown.

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Section: Introductionmentioning

confidence: 99%

Relationships between milks differentiated on native milk fat globule characteristics and fat, protein and calcium compositions

Couvreur

Hurtaud

2017

Animal

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“…The native MFGM consists of a complex mixture of proteins, glycoproteins, enzymes, phospholipids, cholesterol and other minor components [7]. The structure in trilayer, thickness (∼ 10 nm) and composition of the native MFGM depends on the secretion process [8][9][10]. The MFGM acts as a natural emulsifying agent that prevents aggregation and coalescence of milk fat and also protects the fat against enzymatic action, mainly lipolysis [11].…”

Section: Introductionmentioning

confidence: 99%

Focus on the supramolecular structure of milk fat in dairy products

Lopez¹

2005

Reprod. Nutr. Dev.

116

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-Bovine fat is dispersed in raw milk as natural milk fat globules, with an average diameter of 4 µm, which are enveloped in a biological membrane, the milk fat globule membrane (MFGM). However, dairy processes modify the supramolecular structure and the surface composition of milk fat. Thus, milk fat is present in many dairy products under various forms. In this study, we focused on the fact that natural milk fat globules are rarely consumed in their native state, i.e. in fresh raw milk. In most drinking milks, fat globules are homogenised in order to avoid their rising at the surface of the products. Furthermore, fat globules are heat treated to avoid the growth of micro-organisms. As a consequence of the technological process applied, the volume-weighted average diameter of fat globules in drinking milks is in the range 0.2-0.5 µm. Homogenisation of fat globules led to the partial disruption of the MFGM and to the adsorption of milk proteins. Moreover, this study showed that in cheeses, milk fat can be dispersed as (i) fat globules with the MFGM, (ii) aggregates of fat globules, (ii) homogenised fat globules, (iii) free fat and (iv) a combination of different phases and structures. The knowledge of the supramolecular structure of milk fat in dairy products is of primary importance regarding its technological, sensorial and nutritional properties. milk fat / microstructure / confocal laser scanning microscopy

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“…More than 95% of the mass of lipids in cow's milk is present in the form of spherical milk fat globules (MFG) [16], with a diameter ranging from 0.1 µm to 15 µm and a volumetric average around 4 µm [33]. They are surrounded by a native biological membrane, allowing them to be compatible with the aqueous environment: the milk fat globule membrane (MFGM).…”

Section: Introductionmentioning

confidence: 99%

The size of native milk fat globules affects physico-chemical and functional properties of Emmental cheese

Michalski¹,

Camier²,

Briard³

et al. 2004

Lait

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-Emmental cheeses were produced using either small (~3 µm, SFG) or large (~6 µm, LFG) native milk fat globules obtained by a patented microfiltration process. Ripened SFG cheeses were less flexible and less firm than LFG cheeses. Indeed, the SFG cheeses contained more moisture and underwent greater proteolysis than the LFG cheeses 52 d after manufacture. However, lipolysis was three-fold lower in SFG cheeses. This was linked to the milk fat structure in Emmental cheese: larger inclusions of denuded destabilized fat were observed in LFG cheeses, whereas more fat globules were observed in SFG cheeses. One Emmental cheese was produced using homogenized milk fat globules, in which lipolysis was dramatically increased and unacceptable. For a given size range, the structure of milk fat is thus of tremendous importance regarding lipolysis and small natural milk fat globules cannot be replaced by homogenized ones. The melting temperature and solid fat content of fat in Emmental cheese increased with native fat globule size. This is related to the improved functional properties of SFG cheeses, i.e., increased stretching, elastic increase and melting, and lower extrusion force compared with LFG cheeses. This study confirms, as previously pioneered using Camembert cheese manufacturing technology, that the use of native milk fat globules with different sizes can lead to a range of new dairy products with different physico-chemical and functional properties.Milk fat / fat globule / Emmental cheese / cheese yield / rheology / particle size / microfiltration / functional property Résumé -Des propriétés physico-chimiques et fonctionnelles de l'emmental sont affectées par la taille des globules gras natifs du lait. Des emmentals ont été fabriqués en utilisant des globules gras natifs du lait de petit diamètre (~3 µm) ou de grand diamètre (~6 µm), obtenus par un procédé de microfiltration breveté. Les fromages affinés à petits globules sont moins souples et moins fermes que ceux à gros globules. En effet, les fromages à petits globules sont plus humides et plus protéolysés à 52 j d'affinage. Cependant, la lipolyse est trois fois moindre dans les fromages à petits globules, ce qui est lié à la structure de la matière grasse dans les emmentals : les emmentals à gros globules présentent de plus grandes inclusions de matière grasse déstabilisée, tandis que ceux à petits globules semblent contenir plus de globules gras. Un emmental a été fabriqué avec des globules * Corresponding author: mcmichal@labtechno.roazhon.inra.fr 344 M.-C. Michalski et al.

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Intracellular Origin of Milk Fat Globules and the Nature of the Milk Fat Globule Membrane

Cited by 107 publications

References 121 publications

Relationships between milks differentiated on native milk fat globule characteristics and fat, protein and calcium compositions

Relationships between milks differentiated on native milk fat globule characteristics and fat, protein and calcium compositions

Focus on the supramolecular structure of milk fat in dairy products

The size of native milk fat globules affects physico-chemical and functional properties of Emmental cheese

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