Chilled paddy rice grains applied directly to industrial processing have a better head rice yield

Abstract

Rice is important for food security around the world, and the search to minimize losses and obtain the highest rate of head yield grains during processing is a recurring demand. In this context, the aim of this study was to understand the impact of grain conditioning temperature, when subjected directly to husking and polishing, on head rice yield. For this purpose, commercial brown rice grains from two locations and red rice grains from one location in the state of Rio Grande do Sul were studied. The grains were stored at temperatures of 15 °C, 20 °C, 25 °C and 30 °C. The following comparisons were made: a) Unhusked grain: Rice in the husk stored at different temperatures for 7 days and husked; b) Polished: Rice in the husk stored at different temperatures for 7 days, husked and stored for a further 7 days at different temperatures and polished; and c) Complete polished: Rice in the husk stored at different temperatures for 7 days, husked and polished in immediate sequence. The head yield of whole and polished grains was quantified according to the above tests. The results show that for both brown and red rice, storage at 15 °C, when subjected directly to the husking and polishing stages, represents a higher yield head rice, about 1.7% in polished grains when comparing 15 and 30 °C, possibly due to the increased hardness of the grains, as verified by the texture, with a financial impact of approximately R$ 540 million on the Brazilian rice market.