The process provides cereal makers with a cheaper production method by streamlining the previous method for making multigrain flakes, Swiss-based Buhler says. The method uses a preconditioner added to the mix, allowing manufacturers to skip the precooking stage.
Multigrain cereals meet the demand from health-conscious consumers who want more fibre in their diets. National dietary guidelines generally advise people to consume between 25g to 30g of fibre a day, including those sourced from whole grains such as rice.
As the "wellness" movement gains momentum, demand has also been rising over the past few years for breakfast cereals made from several grain varieties but including less sugar, said Christopher Rubin, who heads Buhler's product management team.
Compared with the production of "standard" breakfast cereals, the production of multigrain flakes requires a special process, Rubin said. To meet consumers' needs for multigrain flakes, food makers have been including rice as a component in the breakfast cereals production process.
Because the grains have to be precooked for this purpose, they have had to include a batch cooker in the process. The equipment precooks individual batches of grains in an extended process before they are intermixed in the extruder with the flours and other ingredients.
"The processing of flours, whole grains, rice, and other ingredients is not possible in a single process operation," he told FoodProductionDaily.com. "An existing line to produce extruded cornflakes can be easily updated to produce then the multigrain type flakes. This update can easily be done by using an pre conditioner which we use also to pre cook other materials in a pre extrusion process."
However, the expanded process was found to have a number of drawbacks. The separate cooking of the grains takes a very long time and cannot be interrupted or be controlled with high precision, Rubin said.
" The cooking process therefore dictates the entire production process," he said. " Other disadvantages include the high moisture degree during cooking, which necessitates energy-intensive intermediate drying, and the high capital cost of the batch cooker."
Instead of applying a drum precooker, an existing Buhler preconditioner was modified and integrated in the multigrain process. In the conditioner, the grains are not precooked in batches, but continuously.
This allows direct and continuous feed of the material to the final mixing stage inside the extruder. It takes only a few minutes for the material to pass through the machine, which is much less time than required by batch cooking.
The precooking process can be interrupted and modified whenever necessary. The conditioning is done with a lower moisture content, reducing the energy requirement for drying.
The entire precooking process is integrated in the fully automatic overall production process, he said. This eliminates the need for separate operator attendance and reduces the associated costs.
Together with the lower capital investment - a conditioner costs about half as much as a batch cooker - and the drastically reduced process costs, the new Buhler Multigrain process cuts costs significantly.
He cited numerous advantages gained through use of the technique, including shorter processing times, lower energy consumption and smaller investment costs.
"A start and stop of the production can easily be done because we have a continuous process and not a batch wise process," he said. "Also because of the fact that the process is continuous, the tuning of the process is much easier. You quickly can see results."
The maximum moisture level of the process is lower, because the cooking is done with steam and not with excess water in a big batch cooker.
"Therefore the energy consumption is lower," Rubin said. "We do not have to dry down so much. Also the investment costs of such a line are lower and additionally, the line is more flexible. The integrated extruder can also be used to produce a wide range of other breakfast cereals."
A number of European companies have already installed or are in the process of using the new process, he said. He declined to name the companies, citing Buhler's policy of not identifying its clients.