Miller Magazine Issue: 138 June 2021

83 ARTICLE MILLER / june 2021 “We can’t influence the protein content in the wheat kernel, but we can control and steer starch damage and consequently the quality of the end-product,” says Urs Dübendorfer, Senior Advisor at Bühler. “Each market has its specific characteristics and requirements. The most successful players in the market will be the ones who keep tightly to consistency parameters.” Operators typically check samples of the product in the lab on a regular basis, as the setting of the rolls might shift slightly during operation. The Arrius is the first serial solution to automate this task. By measuring the grind- ing force on both sides of the rollers it provides a clear indication of the status of the grinding work and con- sequently ensures that grinding performance remains stable throughout. In combination with the data on the flow rate, this enables millers to produce a consistent, high-quality product. Adjusting starch damage and particle size distribution for different requirements In the process of grinding, the rollers apply two differ- ent forces on the grist: friction, as the two rollers rotate at different speed, and pressure. Overall, friction creates smaller particles, resulting in a finer flour, but does not break up the miniscule starch granules. Grinding pres- sure on the other hand is strongly correlated to starch damage. “When starch granules are damaged, it’s like the raincoat has been taken off and water and enzymes can get in,” says Dübendorfer. Different products and markets demand different grades of starch damage. Pasta and noodle production requires low levels of starch damage as this results in less water needed to reach the right level of viscosity for the dough. Consequently, energy can be saved in the drying process. A typical Japanese noodle producer demands a fine flour but little starch damage. Here the consistency of particle sizes also plays an important role. For other products higher levels of water absorption are required, which in turn need a higher degree of starch damage. These are typically products with shorter fer- mentation times, such as toast. Achieving the correct particle size distribution on a consistent basis is key to the quality of the end product. “Particle size distribution can change the overall amount of surface of the flour by a huge factor. It is essential to have full control over it,” says Dübendorfer. “This way operators can ensure that the right amount of water con-