Avaliação da qualidade de grãos de diferentes cultivares de arroz irrigado na fronteira oeste do Rio Grande do Sul

Abstract

The quality of irrigated rice grains is a fundamental factor for its commercialization. In this sense, the objective of this study was to evaluate the industrial quality of eight irrigated rice cultivars, two of them (IRGA 424 and IRGA 409) provided by industry and the others (IRGA 431. BRS Catiana, BRS Pampeira, Agro Norte 9027, XP 113 and XP 117) were harvested in rice area irrigated by central pivot. The experiment was conducted with grains produced in 2018/2019 in the region of West Frontier of Rio Grande do Sul. The following cultivars were analyzed: BRS / IRGA 409, IRGA 424, IRGA 431, BRS Pampeira, BRS Catiana, Agro Norte 9027 and the hybrid cultivars XP 113, XP 117. The following evaluations were performed: I) The humidity degree of the samples by the official greenhouse method for 24 hours at 105 ± 1 ° C; II) industrial yield (percentage of whole and broken grains), III) Incidence of defects, IV) Gelatinization temperature and V) After processing, the grain length (C), width (L) and thickness (E) were measured using a digital caliper. The results indicated that the cultivars BRS Catiana and IRGA 431 have the highest humidity levels above 14%, the maximum value allowed by the rice marketing legislation. The cultivars IRGA 409, IRGA 424, IRGA 431 and BRS Pampeira presented the highest yield of whole grains, the values ranged from 55.94% to 63.28% and BRS Catiana, Agro Norte 9027, XP 113 and IRGA 431, high. percentage of broken grains, which ranged from 3.87% to 11.58%, however the values are in accordance with legislation allowing up to 8% of broken grains for Type 1 and 13% for Type 2. The IRGA 424 cultivars presented the highest incidence of defects, especially the cast and white belly grains, which are defects caused by pest attacks and / or early harvest, with high humidity. The cultivars with the highest grain length / width ratio values are BRS Pampeira, IRGA 409 and IRGA 431. All evaluated cultivars fall into the long fine grain class. Regarding gelatinization temperature, only BRS Catiana and Agro norte 9027 were classified as intermediate temperature, in the range of 70 ºC to 74 ºC, the other cultivars present grains with low gelatinization temperature, around 55 to 69 ºC. Thus, it is concluded that the cultivars BRS Pampeira and IRGA 431, obtained excellent results in relation to what the industry proposes to the producers, which is the low incidence of defects and good yield of whole grains, together with the cultivar IRGA 409, in which we refer to these issues.