Stationary rice drying: Influence of initial moisture contents and impurities in the mass grains on the physicochemical and morphological rice quality

Abstract

The initial moisture contents and impurities in the grain mass can interfere with the drying operation in a stationary dryer. Thus, the objective of this study was to evaluate the effect of drying air movement in the rice mass as a function of initial moisture contents (19, 18, 17, and 16% w.b.) and impurities (1.5, 2.5, 2.0, and 3.0%) on the physicochemical properties and morphological rice quality. The moisture and impurity contents provided alterations in the movement and distribution of the drying air in the upper layers of the stationary dryers. Consequently, the physicochemical properties and morphological quality of rice were altered. In addition, the reduction in the starch and fat contents was correlated to higher percentages of crude protein, mainly upper grain layers. Thus, the rice mass at moisture content of 17% (w.b.) and impurity at 2.5% allowed major uniformity and greater drying versatility in the stationary dryer for rice quality. Practical applications The rice drying in the stationary dryer is an excellent option to reduce drying and storage infrastructure and achieve satisfactory grain quality, as long as there is an adequate control and management of the batches of grain received in terms of moisture uniformity and impurity contents. For proper rice management in the stationary dryer, it is recommended to pre‐cleaning the grain mass to 2% of impurities, while the initial grain moisture content for drying must be below 18% (w.b.). The standardization of batches in terms of initial moisture content and impurities allows for an adequate flow and distribution of air in the grain mass to obtain efficiency in drying at low temperatures and maintaining grain quality. From a commercial point of view, the grains can remain in the drying process and stored in silo‐dryers for the harvest period until the time they can be sold at better market prices.

Spatial variation of moisture content along the axial distance of corn at different superheated steam drying temperatures and various instantaneous times

“…The primary task is drying because it is crucial to the outcome of the storage and processing phases that follow. According to Coradi et al [4], drying must be done properly so that the properties of the grains and their derivatives are not affected by controlling the drying temperature [5] and the grain mass temperature [6]. Drying is the process of getting rid of specific quantities of water from materials through evaporation when applying heat under controlled conditions [7].…”

Numerical simulation of rice drying process in a deep bed under an angular air duct

“…Rice is one of the important grains that are part of the daily diet of millions of people worldwide, providing energy, vitamins, and minerals (Müller et al, 2022). Choosing a stationary dryer to dry rice is an excellent choice to reduce drying and storage infrastructure and achieve satisfactory grain quality (Nunes et al, 2022).…”

Drying and intermittence processes on the polished and brown rice physicochemical and morphological quality by near-infrared spectroscopy, X-ray diffraction, and scanning electron microscopy

“…While conducting the drying process, several factors should be taken into consideration for the optimization of the process in order to be reconciled: high energy efficiency, high operational capacity, and the qualitative maintenance of the grains ( Nunes et al, 2022 ). Cracked grain resulting from drying is a major challenge for the rice industry, because the grain structure that was compromised in drying can break later, in the burnishing process, leading to reduced whole grain yield ( Igathinathane, Chattopadhyay & Pordesimo, 2008 ).…”