GEA Westfalia Separator has opened up a new marketing opportunity for the industry with the processing of cream into butter oil or anhydrous milk fat (AMF).
Butter oil is obtained by withdrawing almost all water and the non-fat solids from the cream. At 42 °C it is completely liquid and yellowish in colour. On the world market, the guidelines of the codex alimentarius classifies butter oil products, for example, as AMF (anhydrous milk fat) with a fat content of at least 99.8 percent. The AMF is produced only from fresh raw material of top quality.
Butter oils have many uses, from the recombination of milk and dairy products made of milk powder and butter oil, to fat for deep-frying or also as a raw material for other foods such as baked goods or ice cream.
Its particular experience in the dairy industry allows GEA Westfalia Separator to supply turnkey process lines for obtaining butter oil. Highquality buttermilk is also formed as a by-product of the butter oil process.
As with the production of butter, the initial objective is to damage the membrane of the fat globules to effect a phase inversion. The breaking down of the oil-in-water emulsion and separation of all non-milk fat components is the key objective of the butter oil process. It is possible to use mechanical energy to break open the membranes of the fat globules. The release of fat and the associated phase inversion are effected by a homogenizer mechanically dividing the intact fatty bodies. However, complete concentration is not possible in a single step, which is why separation of the oil and serum phases is also required.
In general, high-performance, self-cleaning separators are used for separation. As an intermediate layer, the emulsion phase causes problems for the separation process which can only be addressed by special design features for the separators in conjunction with optimized process management.
Cream with a fat content of about 40 percent is fed to this system and initially heated to 55 to 60 °C in a plate heat exchanger. This temperature is required to ensure that the cream to be concentrated in the separator bowl has as low a viscosity as possible and, at the same time, as great as possible a difference in density from the skimmed milk. A cream concentrator then concentrates the cream to a concentration of up to 75 percent fat. The concentrated cream is pumped to the phase inversion unit. The buttermilk is discharged from the separator to buttermilk storage.
The highfat cream is inverted under high pressure in the homogenizer. In the oil concentrator which follows, emulsion and β-serum are separated as the heavy phase from the light oil phase and returned for cream concentration. The light oil phase on the other hand, with a concentration of 99.5 percent is heated to 90 to 95 °C and washed in an oil polisher. The residual moisture evaporates in the vacuum evaporator. The butter oil obtained has an oil content of at least 99.8 percent at this process stage and thus meets the standards of the top quality class.
GEA Westfalia Separator now provides system concepts between 1000 and 12,000 kg / h. A concept for discharging α-serum and β-serum is also possible on request. This results in added value from by-products.