Physical properties and effective thermal diffusivity of soybean grains as a function of moisture content and broken kernels

Self Cite

The main objective of this study was to optimize the infrared radiation (IR) drying of parboiled rice on the temperatures of 70, 100, and 130°C and grain bed depth of 5, 10, and 15 mm. The effects of the temperature and grain bed depth on drying kinetics, head rice yield (HRY), milling and color parameters, and cooking properties were evaluated using response surface methodology. The drying temperature and bed depth presented a significant effect on HRY, whiteness, transparency, milling degree, L*, C*, relative crystallinity, cooking time, leached amylose, solubilized protein, and hardness. The longer exposure times to IR resulted in grains with an increase in the intensity of endosperm fissures and lower HRY. There is a tendency that the best condition to dry parboiled rice with IR is at higher temperatures and lower grain bed depth. Practical applications The present study optimized infrared radiation drying of parboiled rice as a function of the drying temperature and grain bed depth. The results provide scientific support on making decision during industrial rice processes. Severe infrared radiation drying conditions can reduce the HRY, increase cooking time, and intensify undesired sensory attributes.

Section: Methodsmentioning

confidence: 99%

Infrared radiation drying of parboiled rice: Influence of temperature and grain bed depth in quality aspects

Timm

Lang

Ferreira

et al. 2020

Self Cite

“…Pohndorf et al () investigated the influence of broken kernels and moisture content on some physical properties of soybeans, especially thermal diffusivity. A metallic cylinder was filled with soybeans and taken to an oven for a certain period of time.…”

Section: Introductionmentioning

confidence: 99%

“…The first one consisted in applying the Ball and Olson (1957) developed modeling heat transfer through to the method of finite difference in three-dimensional. Pohndorf et al (2017) investigated the influence of broken kernels and moisture content on some physical properties of soybeans, especially thermal diffusivity. A metallic cylinder was filled with soybeans and taken to an oven for a certain period of time.…”

Section: Introductionmentioning

confidence: 99%

A simple method to estimate the thermal diffusivity of foods

Mari

Ferreira

et al. 2018

This work shows an alternative method to determine the thermal diffusivity of wheat flour and cassava, by means of experiments. It was considered as a model for analysis a semi‐infinite solid, represented by an aluminum container filled with flour, an incandescent lamp as a heat source and thermocouple sensors for acquisition of electronic temperature signal. From the moment in which the temperature on the upper surface of flour remained constant, the data were acquired at a predefined time interval, which allowed obtaining the thermal diffusivity. To evaluate the results achieved from the experiments, it was carried out a simulation in Partial Differential Equation Toolbox of Matlab R2015a, in order to compare the temperature distributions within the solid. It was verified that the values showed by simulation are satisfactorily close to the experimental values. Practical applications Some information about physical properties of foods usually are not available, therefore, a simple method to estimate the thermal diffusivity could be useful, once it influences the quality control of foods. Thus, the findings of this study may facilitate the food industry, assisting the design, and simulation of process, such as heating, cooling, freezing, defrosting, frying, and storage.

“…The moisture levels in soybean grains may affect physical properties such as density, porosity, and diffusivity significantly (Pohndorf et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Soybean drying as a moving boundary problem: Shrinkage and moisture kinetics prediction

Guilherme

Nicolin

2020

In this work, the diffusion of moisture in the drying process of soybean grains is mathematical modeled considering shrinkage. Moisture and radius data as a function of time were obtained by experimental tests in a drying oven for three different drying temperatures. Radius decrease was registered by image analysis. The parameters of the diffusion model were obtained by nonlinear regression. The model provided diffusivity values and drying constants at the surface of the grains as a function of temperature. The average moisture profiles presented good agreement with the experimental values. Although the radius profiles predictions presented higher deviation when compared with the experimental values, a good agreement were found, especially at the higher drying rates of the process. The model provided good predictions of the moisture and radius profile for the drying process of soybean grains and the diffusivities and drying constants for considering the grain shrinkage during the process. Practical Applications Diffusion coefficients are crucial parameters to be estimated in order to design highly efficient drying process for food industry. Thus, if the mass transfer is mathematically modeled considering realistic aspects, which occur during the drying process, such as the shrinkage of the grains, the diffusion coefficients estimated become more trustable, allowing the project and optimization of drying equipment for the grain processing industry.