Measured and predicted temperature of maize grain (Zea mays L.) under hermetic storage conditions

Abstract

The physical properties of grain, such as temperature and moisture content are two key factors in grain storage. Temperature and relative humidity are two crucial factors for stored grain. In this study, three different storage conditions (room temperature at , 25°C; cooling at , 4 °C; and freezing at , -20°C) were investigated. Yellow dent corn (Zea mays L.) maize(variety Blue River 571136) from Iowa, harvested in 2011 was used. Maize grain was stored in two hermetical sealed binsarrels (50-cm diameter x 76-cm height). Five logger sensors were installed inside the cylindrical bin to measure temperature and relative humidity of the maize graingrain. The sensors were located at the top, center, bottom, left and right at about 12 cm part. After placing each barrel into storage condition, temperature and relative humidity values were measured every minute for 9 days throughout the duration of the experiment. Model validation was carried out by comparing predicted with measured maize grain temperature data data in three differences points of plastic cylindrically bin the radial and vertical directions. arrel.The temperature in the hermetically sealed cylindrical bins varied, mostly in the radial direction and very little in the axial vertical directions. No noticeable change in temperature was observed in room condition. Moreover, the temperature in the grain changed more rapidly in the freezing conditions than in the room and cooling conditions. Furthermore, the lag time between the center temperature and the side (right, left, top, and bottom) was greater in the radial direction as compared to vertical temperature. Model validation was carried out by comparing predicted with measured maize temperature data in three differences points of plastic cylindrically barrel. Predicted data were closely followed measured data. The model can be used to predict the grain temperature changes in room, cooling and freezing under hermetic conditions.The maximum difference between predicted and measured temperature was ±1.5°C. The predicted and measured values of maize grain temperature at radial and vertical directions were found to be in good agreement. The model shows a good potential application to predict the temperature of maize grain stored at room, cooling and freezing conditions under hermetic storage. Key words: Maize; mathematical model, heat transfer; ggrain temperature, grain storage, hhermetic storage, modeling.