Chemical changes in bovine milk fat globule membrane caused by heat treatment and homogenization of whole milk

Abstract

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.

Technical difficulties and future challenges in isolating membrane material from milk fat globules in industrial settings – A critical review

“…This effect was enhanced with increased temperature and heating time. PAS 6/7, assumed to be located at the periphery of the MFGM, was highly susceptible to this effect in particular, and was lost to a large degree (Lee & Sherbon, 2002;Ye et al, 2002). .…”

Development of Tea Whitener Using Concentrated Whey and Milk Solids

“…Interaction between denatured whey proteins and casein micelles might be causing the higher viscosity. Lee and Sherborn [29] have reported heat treatment after homogenization leads to binding of whey proteins to fat globular membrane protein leading to increased viscosity. The ability of whitener to resist feathering (coffee stability test) and provide optimal whitening is presented in Table 7.…”

Enzymatic–fluorometric quantification of cholesterol in bovine milk

“…loss of original membrane components, such as TAG, phospholipids, lipoproteins and proteins (Houlihan, Goddard, Nottingham, Kitchen, & Masters, 1992a;Houlihan, Goddard, Kitchen, & Masters, 1992b), because the fat globules fuse and the reduction in surface area. In addition, a common effect of heating is that milk serum proteins will interact with the MFGM (Kim & Jimenez-Flores, 1995;Lee & Sherbon, 2002).…”