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GEA’s ability to process cream into butter oil or anhydrous milk fat (AMF) has created new marketing opportunities for the dairy industry.
Butter oils have many uses, from the recombination of milk and dairy products to frying fat and as a raw material for baked goods and ice cream. And as the global population continues to grow, butter oil is becoming a strategically important foodstuff.
Many years of experience in the design of separators and decanters, as well as a wealth of expertise and technical know-how, are the cornerstones of our innovation. GEA offers turnkey process lines and installations to produce butter oil with capacities of up to 18,000 kg/h. Depending on the customer’s specific requirements, the process can be designed as batch-based or continuous.
Butter oil is obtained by almost completely removing the water and fat-free dry matter from the cream that’s obtained during the separation of raw milk. A liquid at 42 °C, butter oil is defined by the Codex Alimentarius as AMF (anhydrous milk fat) with a fat content of at least 99.8%.
Breaking down the oil-in-water emulsion and separating the non-milk fat components is the key objective of the butter oil process. Using mechanical energy to rupture the fat globule membranes, a homogenizer can be used to release the fat and effect the associated phase inversion. However, a two-step process is required to fully separate the oil and serum phases.
High-performance, self-cleaning separators are generally used for the process. However, the intermediate emulsion phase can interfere with the separation process; this can only be addressed with special design features and optimized process management.
Cream with a fat content of approximately 40% is fed into the system and heated to 55–60 °C in a plate heat exchanger. This temperature is required to ensure that the cream to be concentrated in the separator bowl has a low viscosity and, at the same time, has a significantly different density than the skimmed milk. The cream is then concentrated to a fat composition of 75% and pumped to the phase inversion unit. The buttermilk is discharged from the separator and stored, and the high fat cream is inverted under high pressure in the homogenizer.
In the oil concentrator, the emulsion and β-serum are separated as the heavy phase from the light oil phase and returned to the cream concentration step. The light oil phase, with a concentration of 99.5% is heated to 90–95 °C and washed in an oil polisher where the residual moisture evaporates. The butter oil obtained has an oil content of at least 99.8% at this stage and, as such, meets the highest quality standards.
GEA provides complete system concepts with throughputs of 500–18,000 kg/h. A version to discharge α-serum and β-serum is also available, resulting in added value from by-products.