The effects of infrared and hot air drying on some properties of corn (Zea mays)

Due to being one of the most important dietary staple foods in the world, corn (Zea mays) has gained considerable attention. Drying is an essential procedure for safe storage of corn. The objectives of the present study were to investigate the effects of infrared (IR), hot air (HA) and infraredhot air combined (IR-HA) drying on some properties of corn and to offer an alternative drying procedure with low energy costs. Crude protein, total carotenoid, phenolic acid composition, color parameters (L, a+, b+, chroma, Hue angle, ∆E) and energy expenses of the drying techniques in terms of specific energy consumption (SEC) for unit evaporated water were evaluated. Dent corn samples were hand harvested at regular intervals of fortnight at maturity and the initial moisture contents were 24, 16 and 15%, respectively. Preparation was included kernel manual trimming and granulating. Kernels were dried until the moisture content comes down to 13% with IR, HA and IR-HA combination techniques except for control. All drying treatments were conducted at 45°C. It was observed that IR radiation did not cause any negative impact on the stated properties of corn in noted conditions. Besides, IR and IR-HA drying methods dramatically reduced the drying time. Specific energy consumption values showed that IR and IR-HA combined systems are more effective and economic when the initial moisture content of corn is above 16%. Evaporation of unit water took 12 and 40% less energy in IR drying of corn samples with the initial moisture content of 24 and 16%, respectively, as compared to HA drying alone. Hence, IR drying is considered to be a promising alternative for corn drying.