Novel fractions from the CDM
The CDM exposes the materials fed to it to a range of stresses. The product enters a high-velocity airstream, where it is accelerated, and constrained to follow a spiral path within a cyclone. As a result of the very high airspeeds achieved and the particulars of the cyclone design, particles are exposed to dramatic changes in pressure over short distances and very short times. The consequence of this is to cause water to evaporate explosively at low temperature, so products dry by spalling, rupturing along biological boundaries instead of along the shearlines that are due to external forces. This leads to products with unusual or unique physical and chemical properties:
- Maize (Zea mays) grain, when processed in the CDM under specific conditions, comminutes to grits, a clean germ fraction, and a beeswing-like material composed almost entirely of bran. Wheat can be similarly comminuted, leading to a mixture of coarse flour, germ and bran that appears to have been carefully hollowed out. Conventional sifting technology can separate a clean flour fraction with good baking properties relative to those achieved by conventional roller milling.
- Field peas are a significant protein crop for human and animal consumption. When prepared for culinary use, the dry peas are first dehulled and split. Conventionally, this is done by abrading the hull and impacting the seed until the hull separates. This leads to damage to the cotyledons, reducing the acceptability of the product to the consumer. By tempering the seed to change the strength of the hull, then processing the seed in the CDM under relatively gentle conditions, the hull can be ruptured and removed from the cotyledons with much less abrasion damage. Conventional air sifting is then used to separate the large flakes of hull from the intact cotyledons.
- Whole chestnuts can be comminuted using the CDM. Careful adjustment of the operating conditions leads to the production of a mixture of large flakes of chestnut hull, a fraction that is a soft grit, and a fraction that is soft and fibrous. This fibrous fraction is easily converted to a flour along with the grits. The flour has excellent nutritional value, since it has high content of essential amino acids in its protein, and it has technical properties that mean doughs made from it have sufficient extensibility and strength to produce unleavened baked goods. These include flat breads and pancakes with excellent taste and texture.