Destabilized fat

There is a fundamental problem which must be solved when dealing with whippable emulsions. Before use the emulsion must be sufficiently stable. On the other hand, it must be possible to destabilize the emulsion by mechanical treatment combined with air incorporation (whipping, air pressure, cooling, freezing). The partly destabilized fat globules in the whipped emulsion are important for the stability of the foam structure. There is a... 

The washed cream is destabilized by churning or freezing then the fat (mainly triglycerides) is melted and separated from the membrane material by centrifugation. Cross-contamination of membrane with core material may be considerable, and methods must be carefully standardized. An elaborate scheme for the isolation and fractionation of the MFGM was developed by Brunner and co-workers (Brunner, 1974). 

Figure 7 Left Surface of air bubbles (a) in whipped topping emulsion is completely covered with a thick layer of plate-siiaped fat crystals (c). w = water phase. Right Surface of air bubbles (a) of whipped imitation cream is covered with a monolayer of only slightly destabilized globules (f). Reprinted from reference 22, courtesy of Scanning Microscopy International.

FFE is an extraction method using heptane which measures the churning out of fat during emulsion stabilization9. High protein and low fat content reduce destabilization, whereas the presence of emulsifiers, cold treatment at 5°C and mechanical treatment (whipping, possibly combined with freezing) increases destabilization. 

Foams stabilized with proteins, such as egg white, can be quite sensitive to the presence of oil (fat) droplets (see also Section 5.6.7). Just as is the case with foam sensitivity to oil in other industries, the presence of even small amounts of oil (0.03 mass % in foods [814]) can destabilize a foam. Oils such as lipids are thought to interfere with foaming by displacing proteins from the air-aqueous interface. One approach to improving the foam stability involves combining acidic proteins, such as whey or serum albumin, with basic proteins [814]. 

Boode, K., Bisperink, C., Walstra, P. 1991. Destabilization of O/W emulsions containing fat crystals by temperature cycling. Coll. Surf. 61, 55-74. 

Segall, K.I., Goff, H.D. 2002b. A modified processing routine for ice cream that promotes fat destabilization in the absence of added emulsifier. Int. Dairy J. 12, 1013-1018. 

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