Buhler has developed a roller mill for grains, bean, seeds and cocoa which allows such commodities to be ground into an ultrafine consistency - crucial for effective processing.
The micromilling of soybeans, beans, cereal grains, or high-fibre grain fractions such as oat, barley, or wheat bran pose serious challenges to millers. Even speciality milling equipment such as high-speed pin mills or jet mills have great trouble grinding these materials to the required fineness. Normally, this calls for costly processes involving, say, pin mills in combination with air classifiers or grinding under nitrogen. Moreover, throughputs are normally low in these processes.
To allow such materials to be ground to an ultrafine degree, Buhler has developed a special roller mill: the micromill. Operation of the mill is based on the mortar principle: the machine grinds the material by means of three smooth roll pairs, with one roll in each pair rotating faster than the other. In the narrow roll gaps, the tough kernels are sheared apart by high forces. This ruptures the plant cells, releasing their contents. Superficially viewed, the micro-flakes have a thickness between 10 and 50 microns. They still consist of coherent cell material which will readily dissolve when subsequently used in foods. One micrometer is one thousandth of a millimetre.
Instant soy powder
The goal of the new process is to produce an entirely natural soy powder which can be used directly in beverages and other foods without requiring any aqueous phase. The soybeans are cleaned, hulled and pre-ground. Then they undergo thermal treatment by steam and drying. Finally, the material is micromilled, producing an ultrafine, nutritious soy powder.
Using a patented process, the valuable part of the bran - the aleuron cells - are extracted in a pure form. The aleuron cells are the vital wheat cells located just underneath the cellulose-containing seed skin and adhering firmly to it. During normal flour production, they are separated along with the bran fraction. But since they contain valuable proteins, vitamins, minerals and other active substances, extracting them is extremely promising from the nutritional point of view.
However, these valuable cell contents are surrounded by thick cell walls and cannot be assimilated by the human organism without rupturing the cell walls. Micromilling allows precisely this to be done. An upstream thermal treatment will improve the taste of the product.
Buhler is a global technology group and system partner for plant and equipment and for process expertise in the fields of food processing, chemical engineering and die casting, with a worldwide payroll of about 6,000.