212 Chapter 9
Figure 9.8. Phase inversion of cream for anhydrous milk fat production. GEA Westfalia Separator, Germany.
Figure 9.9. Vacuum drying of anhydrous milk fat. GEA Westfalia Separator, Germany.
The oil is then is cooled to 40 ° C (104 ° F)
for packing. Typically AMF is packed in 1 - to
20 - liter containers for households and restau-
rants and 200 - liter drums for industrial use.
Normally an inert gas, nitrogen, is fi rst
injected into the container, where it sinks to
the bottom. When the AMF is pumped in it
replaces the nitrogen at the bottom of the
container (AMF is heavier) and the nitrogen
gas creates an oxygen - free layer on the
surface of the oil. AMF may be stored at
ambient temperatures for several months.
When AMF is prepared from butter
(see previous butter manufacture section),
unsalted butter is usually used and this is fi rst
melted by indirect means (plate heat
exchanger) to 60 ° C to 70 ° C (140 ° F to 158 ° F).
If direct heating by steam injection is used,