By using a Tomra 3C optical sorting system from Tomra Food to sort puffed grain, the Swiss company Kentaur AG, specialist in cereals processing, has optimized its output. With high sorting performance and accuracy, the new system helps to meet strict requirements for food safety and quality.

Kentaur AG from Lützelflüh/Switzerland is specialized in the refinement of cereals for customers from all over the world. The wide range of innovative, conventional, and organic products, including products developed by Kentaur – from flakes to puffed cereals, coated flakes, and pops to granules – is produced exclusively for private labels and offers consumers throughout Europe and beyond a high-quality alternative to name-brand products. About 70 % of the products are exported. In most cases, they come in shelf-ready packaging – folding boxes with bags or printed stand-up pouches.

For Kentaur, only the best quality will do as international customers expect the highest standards. This applies to everything, from the purchase of raw materials and ingredients from selected suppliers to delivering the finished products in the customer’s desired packaging. The products are subject to constant testing. Andreas Hebeisen, Head of the Supply Chain Department, explains: “We continuously invest in optimizing our standards. Aspects such as sustainability and ethics are essential to us, and we see ourselves as role models here. We succeeded in doing this with the Tomra 3C optical sorting system, which we have been using to sort puffed grain for over a year. Since the system was integrated into our line, the number of complaints has been almost zero.”

The company uses state-of-the-art technologies for the production of puffed grain. Spelt, oats, wheat, and even small grains such as amaranth and quinoa are first pre-cleaned in this process, then pre-heated and saturated with steam in a pressurized vessel at 160 to 180 °C. When the 14 bar pressure is reached, the grains are puffed in the system’s expansion duct in a fraction of a second.

The Tomra 3C optical sorter integrated into the puffing line ensures careful sorting after an initial sieving process – the product stream arrives at the sorter via a three-lane feed. The powerful system sorts 14 kg of puffed grain in just 40 s. It can be used for a wide variety of grains but also vegetables and seeds.

In the plant at Kentaur, the puffed grain, which increases to up to ten times its original size during this process, falls from the funnel onto a shaking pan and is evenly distributed on the feed chute. High-resolution dual laser and camera units check the puffed grain from all sides for various parameters. Just milliseconds later, the intelligent ejection system separates defective products and ejects them via the reject chute. All product that passes this evaluation continues on the good-product chute and is directed into big bags or a corresponding silo, where it is later subjected to coating, for example with liquid sugar, as required, or added to the final packaging.

“The pre-screened good products are checked for discoloration or clumping”, says Andreas Hebeisen. “Our customers do not accept dark grains, for example products with husk remains or products that are overheated.” The system rejects products of the wrong size or colour while also eliminating foreign bodies such as stones, straw, plastic, glass, and others by using a combination of multispectral, pulse-controlled LED lighting technology, double-sided high-resolution RGB cameras, laser technology and innovative analysis software. Thus, the Tomra 3C ensures that cereals meet the highest food safety and quality requirements. At Kentaur, the only additional check occurs when the product passes through a metal detector.

“The new sorting system offers a decisive advantage: it sorts even tiny grains extremely reliably,” explains Andreas Hebeisen. “We also use it for amaranth and quinoa, for example. These are tiny goods that make it difficult to separate the black undesirable product elements from the good dark ones. The changeover to a wide variety of products and sorting features is straightforward and user-friendly. The entire puffing line is looked after by just one employee”.

Kentaur’s decision to acquire the Tomra 3C was made at Tomra Food’s headquarters in Leuven/Belgium. Here, interested parties can test their products with the support of Tomra’s mechanical engineering experts. All of the sorting machines developed by Tomra Food are available for testing at the company’s test centre in Leuven. The results of the tests are discussed and evaluated with the engineering specialists. The tests carried out convinced those responsible at the Swiss cereal specialist. The results were finally confirmed with the installation and commissioning of the system in the Lützelflüh plant. “Throughout the entire process up to commissioning in the factory, we were looked after by the same highly competent contact persons, which created a lot of trust,” states Andreas Hebeisen.

Since installation, the production line including the optical sorting system has been in operation around the clock, sometimes even for several weeks without being switched off. Even with 24/7 operation, regular cleaning is a constant requirement, especially when changing products. If organic or gluten-free products are produced, cleaning is particularly time-consuming and can take 8 to 10 h. Tomra´s hygienic design, which enables the sorting system to be cleaned quickly, is an excellent support for Kentaur employees in implementing fast delivery times, not only at times of high stress.