Interactions of fat globule surface proteins during concentration of whole milk in a pilot-scale multiple-effect evaporator

2004 ◽  
Vol 71 (4) ◽  
pp. 471-479 ◽  
Author(s):  
Aiqian Ye ◽  
Harjinder Singh ◽  
Michael W Taylor ◽  
Skelte G Anema

The changes in milk fat globules and fat globule surface proteins during concentration of whole milk using a pilot-scale multiple-effect evaporator were examined. The effects of heat treatment of milk at 95 °C for 20 s, prior to evaporation, on fat globule size and the milk fat globule membrane (MFGM) proteins were also determined. In both non-preheated and preheated whole milk, the size of milk fat globules decreased while the amount of total surface proteins at the fat globules increased as the milk passed through each effect of the evaporator. In non-preheated samples, the amount of caseins at the surface of fat globules increased markedly during evaporation with a relatively small increase in whey proteins. In preheated samples, both caseins and whey proteins were observed at the surface of fat globules and the amounts of these proteins increased during subsequent steps of evaporation. The major original MFGM proteins, xanthine oxidase, butyrophilin, PAS 6 and PAS 7, did not change during evaporation, however, PAS 6 and PAS 7 decreased during preheating. These results indicate that the proteins from the skim milk were adsorbed onto the fat globule surface when the milk fat globules were disrupted during evaporation.

1996 ◽  
Vol 63 (3) ◽  
pp. 441-449 ◽  
Author(s):  
Milena Corredig ◽  
Douglas G. Dalgleish

SummaryThe heat-induced binding of whey proteins to milk fat globule membranes in whole milk was investigated by quantitative electrophoresis and laser scanning densitometry. Both α-lactalbumin and β-lactoglobulin bound to the surfaces of fat globules when milk was heated in a water bath in the temperature range 65–85 °C. The interaction behaviour of α-lactalbumin did not seem to change with temperature, and the total amount of protein bound was ∼ 0·2 mg/g fat contained in the cream. The quantity of βlactoglobulin interacting with the milk fat globules increased with temperature from 02 to 0·7 mg/g fat between 65° and 85 °C. Even in whole milk heated at batch pasteurization temperatures (60–65 °C), α-lactalbumin and β-lactoglobulin were found attached to the fat globules. The interactions of the whey proteins with intact fat globule membranes were also investigated in milk heated in an industrial system (a pilot scale UHT and high temperature short time module), and the results were compared with those from the laboratory treatment (simple batch heating). The binding of the whey proteins to fat globules differed between milk heated by UHT using indirect steam heating or direct steam injection (DSI). However, the surface load in milk treated by DSI was not comparable to that of milk treated by batch heating or indirect steam heating, because of the changes in fat globule size and membrane composition caused by the DSI process.


2009 ◽  
Vol 390 (1) ◽  
Author(s):  
Fernando Sánchez-Juanes ◽  
Josefa M. Alonso ◽  
Lorena Zancada ◽  
Pablo Hueso

AbstractSeveral components of milk fat globule membranes (MFGMs) have been reported to display beneficial health properties and some of them have been implicated in the defense of newborns against pathogens. These observations prompted us to determine the glycosphingolipid content of MFGMs and their interaction with pathogens. A comparative study with whole milk components was also carried out. Milk fat globules and MFGMs were isolated from milk. Gangliosides and neutral glycosphingolipids were obtained from MFGMs and whole milk and their fatty acid contents were determined by gas chromatography-mass spectrometry (GC-MS). MFGMs and whole milk showed similar ganglioside and neutral glycosphingolipid contents, with whole milk having more GM3 and glucosylceramide and less GD3,O-acetyl GD3,O-acetyl GT3, and lactosylceramide. The fatty acid content of gangliosides from both sources showed a similar composition. However, the neutral glycosphingolipid fatty acid content seemed to be quite different. Whole milk had fewer very-long-chain fatty acids (18.1% vs. 46.4% in MFGMs) and more medium-chain and unsaturated C18:1 and C18:2 fatty acids. Milk fat globules, MFGMs, lactosylceramide, and gangliosides GM3 and GD3 were observed to bind enterotoxigenicEscherichia colistrains. Furthermore, bacterial hemagglutination was inhibited by MFGMs and glycosphingolipids.


2008 ◽  
Vol 75 (3) ◽  
pp. 347-353 ◽  
Author(s):  
Aiqian Ye ◽  
Skelte G Anema ◽  
Harjinder Singh

The changes in milk fat globules and fat globule surface proteins of both low-preheated and high-preheated concentrated milks, which were homogenized at low or high pressure, were examined. The average fat globule size decreased with increasing homogenization pressure. The total surface protein (mg m−2) of concentrated milk increased after homogenization, the extent of the increase being dependent on the temperature and the pressure of homogenization, as well as on the preheat treatment. The concentrates obtained from high-preheated milks had higher surface protein concentration than the concentrates obtained from low-preheated milks after homogenization. Concentrated milks heat treated at 79°C either before or after homogenization had greater amounts of fat globule surface protein than concentrated milks heat treated at 50 or 65°C. This was attributed to the association of whey protein with the native MFGM (milk fat globule membrane) proteins and the adsorbed skim milk proteins. Also, at the same homogenization temperature and pressure, the amount of whey protein on the fat globule surface of the concentrated milk that was heated after homogenization was greater than that of the concentrated milk that was heated before homogenization. The amounts of the major native MFGM proteins did not change during homogenization, indicating that the skim milk proteins did not displace the native MFGM proteins but adsorbed on to the newly formed surface.


Dairy ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 202-217
Author(s):  
Michele Manoni ◽  
Donata Cattaneo ◽  
Sharon Mazzoleni ◽  
Carlotta Giromini ◽  
Antonella Baldi ◽  
...  

Milk lipids are composed of milk fat globules (MFGs) surrounded by the milk fat globule membrane (MFGM). MFGM protects MFGs from coalescence and enzymatic degradation. The milk lipid fraction is a “natural solvent” for macronutrients such as phospholipids, proteins and cholesterol, and micronutrients such as minerals and vitamins. The research focused largely on the polar lipids of MFGM, given their wide bioactive properties. In this review we discussed (i) the composition of MFGM proteome and its variations among species and phases of lactation and (ii) the micronutrient content of human and cow’s milk lipid fraction. The major MFGM proteins are shared among species, but the molecular function and protein expression of MFGM proteins vary among species and phases of lactation. The main minerals in the milk lipid fraction are iron, zinc, copper and calcium, whereas the major vitamins are vitamin A, β-carotene, riboflavin and α-tocopherol. The update and the combination of this knowledge could lead to the exploitation of the MFGM proteome and the milk lipid fraction at nutritional, biological or technological levels. An example is the design of innovative and value-added products, such as MFGM-supplemented infant formulas.


2002 ◽  
Vol 69 (4) ◽  
pp. 555-567 ◽  
Author(s):  
SUNG JE LEE ◽  
JOHN W. SHERBON

The effects of heat treatment and homogenization of whole milk on chemical changes in the milk fat globule membrane (MFGM) were investigated. Heating at 80 °C for 3–18 min caused an incorporation of whey proteins, especially β-lactoglobulin (β-lg), into MFGM, thus increasing the protein content of the membrane and decreasing the lipid. SDS-PAGE showed that membrane glycoproteins, such as PAS-6 and PAS-7, had disappeared or were weakly stained in the gel due to heating of the milk. Heating also decreased free sulphydryl (SH) groups in the MFGM and increased disulphide (SS) groups, suggesting that incorporation of β-lg might be due to association with membrane proteins via disulphide bonds. In contrast, homogenization caused an adsorption of caseins to the MFGM but no binding of whey proteins to the MFGM without heating. Binding of caseins and whey proteins and loss of membrane proteins were not significantly different between milk samples that were homogenized before and after heating. Viscosity of whole milk was increased when milk was treated with both homogenization and heating.


1976 ◽  
Vol 43 (2) ◽  
pp. 283-290 ◽  
Author(s):  
B. E. Brooker

SummaryElectron microscopy showed that a varying proportion of cells ofStreptococcus cremorisNCDO 924 grown in autoclaved skim-milk possessed a layer of extracellular material attached to the cell wall. Occasional filamentous extensions of this layer made contact with neighbouring casein micelles. The same surfacestaining material persisted during the production of cheese-curd, but after maximum scald it was predominantly filamentous in appearance. These filaments made frequent contact with the adjacent curd matrix and with milk-fat globules.Str. cremorisNCDO 1986 produced similar surface material when in curd, but not when grown in skim-milk. In all situations, the extracellular material stained with colloidal iron hydroxide, ruthenium red and periodic acid–thiosemicarbazide–silver proteinate, indicating that it was largely composed of an acidic carbohydrate. It is suggested that this carbohydrate facilitates the adhesion of starter bacteria to the cheese-curd matrix and that during the initial stages of syneresis this serves to prevent their expulsion from the curd with the whey.


1992 ◽  
Vol 59 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Avis V. Houlihan ◽  
Philippa A. Goddard ◽  
Stephen M. Nottingham ◽  
Barry J. Kitchen ◽  
Colin J. Masters

SummaryHeating raw milk at 80 °C for 2·5–20 min was found to result in compositional changes in the milk fat globule membrane (MFGM). The yield of protein material increased with the duration of heating, owing to incorporation of skim milk proteins, predominantly β-lactoglobulin, into the membrane. Lipid components of the MFGM were also affected, with losses of triacylglycerols on heating.


2016 ◽  
Vol 7 (10) ◽  
pp. 4259-4266 ◽  
Author(s):  
Aiqian Ye ◽  
Jian Cui ◽  
Douglas Dalgleish ◽  
Harjinder Singh

The behaviour of milk fat globules in the coagula of unheated and heated (90 °C for 20 min) whole milk during gastric digestion was investigated using a human gastric simulator.


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