The influence of anaerobic conditions of maize grain storage on the changes in the quality parameter “falling number”

In recent decades, at Ukrainian farms and grain-processing enterprises, the technology of storing grain in silo bags has become widespread. In this type of storage, anaerobic conditions are created due to the physiological respiration process, which ensures extended shelf life of freshly harvested grain. This, in turn, allows the use of low-power processing equipment for post-harvest grain processing, which is especially important for wet and moist maize as it requires powerful grain dryers. The article presents the results of a study of the effect that the initial moisture content of maize grain, the temperature and the duration of its storage under anaerobic conditions have on the Falling Number, one of the quality parameters depending on the amylase activity of the grain. The object of the study was grain samples of freshly harvested (in 2017) dent maize, the hybrid DKC 3705, with the average moisture contents 14%, 21%, and 28%, stored under anaerobic conditions for 3 months at temperatures of +18°C, +11°C, and +4°C. The Falling Number was determined by the standardized Hagberg-Perten method on a ПЧП-7 instrument (“Falling Number Apparatus”). Based on the results obtained, histograms of the kinetics of Falling Number changes have been constructed, the analysis of which made it possible to establish patterns of the changes in the Falling Number depending on the moisture content of the grain and the duration of its storage at different temperatures. It has been shown that in the maize grain samples with the initial moisture content 14%, regardless of the temperature conditions during storage for 3 months, there is a steady tendency to a gradual decrease in the Falling Number. In the maize grain samples with the initial moisture content over 14%, at the beginning of storage, there is a period of an increase in the Falling Number, the intensity of which depends on the initial moisture content of the grain and the temperature conditions of its anaerobic storage. After the completion of post-harvest maturation processes in freshly harvested maize grain, its further storage leads to a decrease in the Falling Number. To summarize the experimental data, a nonlinear empirical equation is suggested to describe the patterns of changes in the Falling Number depending on the factors studied: the moisture content of maize grain, the temperature conditions and duration of storage. Considering that the value of the Falling Number is determined by the activity of the amylase complex of the grain, it can be used as an express method of monitoring the state of grain stored in silo bags.