Nutritional composition of grain kernels in different drying processes

Maize is one of the most important agricultural crops due to its adaptability and a wide use in the food industry, animal-feed industry, and in other sectors of the economy. This paper compared the nutritional composition of hybrid and traditional maize varieties (the white and the red maize) under the influence of different drying methods. The samples dried in a fluidized-bed dryer and a vacuum dryer at the temperatures of 60, 70, and 80°C were analyzed. The nutritional properties were determined by the content of protein, starch, fat, and the proportion of the elements such as carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S). These elements’ analysis helps to optimize animal nutrition, increase the utilization of nutrients, and improve production results (milk, meat, and eggs). The study results indicate that the nutritional properties are better preserved during a vacuum drying (VD ), while the maize dries faster in a fluidized bed. The hybrid maize released moisture faster than the conventional varieties. After the vacuum drying, the higher levels of carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) were detected, while a decrease in the protein content was mainly influenced by a higher temperature. The most favorable treatment for protein preservation was the vacuum drying at 60°C, while the highest percentage of starch was established after the vacuum drying at 70°C. The fat content was highest after drying in a fluidized bed at 70°C and the lowest after the vacuum drying at 80°C.