Physical and chemical properties of amaranth grain as affected by the varietal characteristics and humidity

Abstract

Purpose. To establish the peculiarities of the formation of physicochemical properties of amaranth grain under the effect of varietal characteristics and humidity. Methods. Laboratory methods for determination of physicochemical and physicomechanical properties of grain; calculation for determination of volume, area and sphericity of grain; mathematical and statistical methods for the analysis of the experimental data. Results. The research shows that the carbohydrate content of amaranth grain varied from 63.1 to 68.7%. At the same time, the content of carbohydrates in the grain of variety ‘Kharkivskyi-1’ was significantly higher compared to ‘Atstek’ and ‘Helios’. The content of protein in the grain of the studied varieties varied significantly. The highest protein content was in the grain of 'Lera' and ‘Kharkivskyi-1’ varieties (20.2–24.9%). It should be noted that the lysine content in the grain of these varieties was also the highest (0.85–0.91%). Grain moisture content in the studied varieties was low (8.3–11.1%). The highest grain quality was in the ‘Helios’ variety – 819 g/dm3, while in the rest of the studied varieties it ranged from 748 to 775 g/dm3. 1000-kernel weight and 1000-kernel volume were almost equal in the studied amaranth varieties. At the same time, the angle of the natural slope varied reliably. The coefficients of external friction at rest and the coefficient of external friction in motion for the grain of the varieties ‘Kharkivskyi-1’, ‘Lera’ and ‘Atstek’ were significantly higher compared to ‘Helios’. The geometric parameters of grain changed reliably depending on their humidity: as the humidity of the grain increases, its geometric parameters increase. An increase in the moisture content of the grain increases the linear dimensions. At the same time, the volume and surface area of the grain increases, thanks to which the sphericity increases. Conclusions. It was established that the physicochemical properties of amaranth grain reliably change as affected by varietal characteristics and humidity. The grain of amaranth varieties ‘Lera’ and ‘Kharkivskyi-1’ has the highest protein content (20.2–24.9%) and lysine (0.85–0.91%). The carbohydrate content is 65.3–68.7%. ‘Helios’ variety has the highest grain quality – 819 g/dm3. 1000-kernel weight is 0.664–0.710 g, depending on the variety. The grain of varieties ‘Kharkivskyi-1’, ‘Lera’ and ‘Atstek’ is characterized by a higher angle of natural slope, coefficients of external friction at rest and external friction in motion. An increase in grain moisture significantly increases its geometric parameters.