Influence of polishing degree on technological traits of grain of different rice varieties

Background. The quality of rice products, their physical properties and nutritional value depend on the degree of grain processing, including its polishing, which removes the surface shells and the germ. The task of the work is to assess the effect of the degree of grain polishing of Russian-bred rice varieties with different grain sizes and shapes on the physical (technological) traits of the grain.

Purpose. The goal of the study was to assess the influence of the grain polishing degree of Russian-bred rice varieties with different grain sizes and shapes on the physical (technological) traits of the grain.

Materials and methods. The research material included the following varieties: Favorit, Veles, Trio, Regul 2, Forsazh, Strombus, Prestige, Vector, most of which are approved for use. The set of parameters for assessing grain quality included the following indicators: grain size, vitreousity, grain fracturing, total milling yield, head rice content, and bran yield during polishing. The duration of polishing was 50, 90, and 120 seconds.

Results. The mass of 1000 absolutely dry grains was in the range of 25.6–26.6 g in the group of medium-weight varieties and 28.4–33.1 g in the group of large-grain rice varieties. In the group of large-grain varieties, the varieties Forsazh and Strombus were the most resistant to intensive polishing, the varieties Prestige and Regul 2 were the least resistant; in the group of medium-weight varieties, the corresponding indicators of the head rice content were significantly lower.

Conclusion. Significant dynamics of the indicators was noted already at the initial stage of grain polishing (90 s) in the rice varieties Favorit and Strombus for the indicator “head rice content”, Favorit and Utes - for the bran yield; at the stage of 120 s - in the vari-eties Regul 2 and Vector, Prestige for all traits, the varieties Trio and Forsazh for the indicators “total milling yield” and “bran yield”. Equivalent changes in the indicator of traits with different degrees of polishing were typical for the varieties Strombus and Utes for the indicator of total milling yield; Trio, Utes and Forsazh- for the head rice content and the variety Strombus - for the bran yield.