Perda de massa, desempenho industrial e qualidade de cocção do arroz em casca armazenado por um ano em diferentes condições de umidade relativa

Abstract

Rice storage represents a crucial stage in the production chain, as it can significantly impact the final quality of the grains, especially under inadequate humidity conditions and prolonged periods. Physical, chemical, and microbiological changes may compromise the industrial yield, visual appearance, and technological performance of the grains during cooking. This study aimed to evaluate the effects of air relative humidity (65%, 75%, and 85%), initial grain moisture content (10.2% and 14.5%), and storage duration (0, 3, 6, 9, and 12 months) on the quality of IRGA 424 RI rice grains. Physical, chemical, and microbiological parameters were analyzed, including mass loss, milling yield, head rice yield, whiteness and color profiles, acidity index, fungal incidence, viscoamylographic properties (RVA), and multivariate analyses (PCA and Pearson correlation). The results showed that storage time and relative humidity strongly influenced the analyzed attributes. Grains stored at 85% relative humidity showed greater qualitative losses, with increased activity of storage fungi such as Penicillium spp. The 75% condition provided greater stability over time. A higher initial moisture content (14.5%) favored the preservation of head rice yield, final viscosity, and titratable acidity, especially under environments with lower relative humidity. However, under high relative humidity conditions (85%), the elevated initial moisture content intensified losses, showing that its effectiveness depends directly on the storage conditions. Multivariate analysis confirmed clustering patterns among treatments and revealed a transition in fungal microbiota, with a predominance of field fungi at the beginning and typical storage environment fungi, such as Penicillium spp., in the more advanced stages. It is concluded that controlling air relative humidity and the duration for which the rice remains stored is essential to minimize losses and preserve its quality.