Joint effort results in new colour extrusion process

By staff reporter

- Last updated on GMT

Related tags: Color

In a joint effort with one of its customers, Bühler claims to have
developed a more efficient method of extruding multicoloured
foods with a single machine.

The Switzerland-based company did not reveal the name of its client. However the process was developed with a customer who wanted a cheaper, more flexible method of producing coloured breakfast cereals. Current processes for extruded multicoloured foods use a variety of different methods. One option is to operate several extruders in parallel, with each machine producing a specific product colour. Another method is to produce production batches of different colours and them mixing them at the end. A third option is to spray on the different colours on the extruded foods. "All these processes have their specific drawbacks, which increase costs and space requirements,"​ Bühler stated in describing the research. The new process uses a single extruder, allowing the continuous production of multicolored foods without requiring any mixing of batches. The heart of the new process is an add-on module made up of various colorant tanks with pumps, along with a system for connecting to the process unit of the extruder. The companies also developed a way to adjust the process geometry to prevent smears from one colour to another during the transitions, Bühler stated. During the production process, the colorants are alternately metered into the process section of the extruder. "The special thing about this approach is that the time intervals are kept very short to eliminate the need for subsequent mixing in an additional stage,"​ Bühler stated. "Mixing during conveying, spraying, and drying is sufficient to obtain a homogeneous mix."​ The system also allows processors to make use of colour properties to obtain intermediate colors. "The development of the new process has paid off,"​ Bühler stated. "The new approach has proved to be superior to the three other methods. Its capital cost is lower and it requires less space, since less equipment is needed."

Related topics: Processing & Packaging

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