Batch drying characteristics of dent corn (Zea mays var. indentata Sturt.)

Abstract

The batch drying characteristics of dent corn were investigated in a batch-type laboratory hot-air dyer over a temperature range of 30-60 degrees C. The results showed that increasing the drying air temperature caused shorter drying times and all of the sample drying occurred in the falling-rate period, with the exception of a very small amount that occurred in the heating-up period. Additionally, the colour and structural changes of fresh and dried corn kernels were investigated. Among all of the drying conditions, the closest values to the colour of fresh corn were obtained at 30 degrees C. Scanning electron microscope images revealed that the low drying temperatures of 30 degrees C and 40 degrees C did not cause clear differences in the granular integrity of the products' starch structures compared with fresh samples. However, the high temperatures of 50 degrees C and 60 degrees C during the drying process caused a more violent evaporation of water and the melting of the starch granules.