Review of grain drying methods at the early stages of maturity

The depletion of traditional feed resources makes the search for alternative raw materials for the feed industry extremely crucial. A heap of early-maturing wheat is of significant interest as a new feed raw material due to its high protein and vitamin percentage. However, its use in feed production is limited by such significant drawback as high moisture content (up to 60 %), which promotes self-heating and microbial growth in the grain mass. To eliminate these negative factors, drying is required to ensure maximum preservation of nutritional value and vitamins in the product. The current review has presented a comparative analysis of such methods for drying early maturing wheat grain as convection, microwave drying, and infrared drying. There have been considered the characteristics of each method and identified their key advantages and disadvantages. There has been established that the infrared drying method is the most effective, since it combines a gentle temperature regime (40–60 °C) with a high speed of the process, which allows preserving maximum nutrients in the finished product. The convective method has been found ineffective due to the high risk of overheating the initial product. Microwave drying should be used primarily at the final drying stage, as it is unprofitable to use it for processing high-moisture raw materials.