Factors influencing maize kernel breakage – a review

Maize (Zea mays L.) kernels are exposed to mechanical and physical impacts during harvest, transport, handling, and processing. Between harvest and processing, there are losses in grain weight and reduced physical quality often occurs. Cracked or broken kernels are quality factors that reduce the efficient use and sales value of maize grain. The adverse influence of mechanical impact on maize kernels ranges from the development of small and large cracks of the pericarp to completely broken kernels, and dust generation. Increasing the amounts of broken kernels results in potential problems during storage due to faster spoilage of grain, difficult and uneven aeration during handling and grain drying, increased risk of spontaneous heating and explosion, increased animal health issues due to reduced utilization rate, and increased respiratory infections of humans and animals, and inefficient processing due to unfavourable ratio of high-value products to low-value products in dry and wet milling. The maize kernel structure, the production system, and the climatic condition’s during the maize growing season influence kernel hardness and brittleness or breakage susceptibility causing differences in the amount of breakage present. During artificial grain drying, high temperatures on the kernel surface lead to internal moisture gradients within grain kernels resulting in increased kernel crackage and breakage.