Propiedades de adsorción de agua de dos genotipos de arroz rojo

Ascheri, Diego P. R.; Bastos, Suely Miranda Cavalcante

doi:10.1590/1809-4430-eng.agric.v35n1p134-143/2015

Cited by 3 publications

(3 citation statements)

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“…Figure 1 shows that the differential enthalpy increased exponentially with equilibrium moisture content reduction, being more pronounced at a moisture content below 10% (d.b.). The same trend was observed by Ascheri & Bastos (2015), who investigated the thermodynamic properties of adsorption of two red rice genotypes.…”

Section: Resultssupporting

confidence: 79%

Thermodynamic Properties of Sorption of Rice in the Husk

et al. 2018

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This study aimed to determine the thermodynamic properties of sorption processes (desorption and adsorption) of rice in the husk, cv. Urucuia. A static-gravimetric method was used to reach equilibrium moisture content at different temperatures (10, 20, 30, 40, and 50 °C ± 1°C) and relative humidity levels (10, 30, 50, 70, and 90 % ± 2%). A decrease in moisture content led to an increment of the integral isosteric heat of sorption, indicating a higher demand for energy to remove moisture from the product. Differential entropy of sorption decreased along with a moisture content increment, with higher values for desorption. This indicates a higher mobility of water molecules during desorption if compared to adsorption. Gibbs free energy decreased with increasing temperature in both processes, with positive values for desorption (endothermic process), and negative for adsorption (exothermic process). The enthalpy-entropy compensation theory is valid for both sorption phenomena (desorption and adsorption) of rice in the husk, being both processes enthalpy controlled.

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Section: Resultssupporting

confidence: 79%

Thermodynamic Properties of Sorption of Rice in the Husk

et al. 2018

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“…There are countless studies that investigated the thermodynamic properties of agricultural products (Moreira et al, 2008;Oliveira et al, 2011;Goneli et al, 2013;Corrêa et al, 2015;Ascheri & Bastos, 2015); however, studies focusing on the mechanical damage in beans are scarce. Based on this, the objective of this study is to investigate the alterations in thermodynamic properties (integral isosteric heat of sorption, differential entropy, Gibbs free energy, and enthalpy-entropy compensation theory) of drying and sorption processes due to controlled damage, which approximates to the practical conditions at the production site and industry.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of water sorption of damaged bean grains: Thermodynamic properties

Corrêa

Baptestini

Bustos-Vanegas

et al. 2017

Rev. bras. eng. agríc. ambient.

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A B S T R A C TThis study aims to determine the thermodynamic properties of damaged beans. Grains with initial moisture content of 53.85% (d.b.) were used. A part of the grains was used to obtain the desorption isotherms, while another part was subjected to drying until a moisture content of 5.26% (d.b.) was achieved; therefore, it was subjected to the adsorption process. To induce damage, a Stein breakage tester was used. To obtain the equilibrium moisture content, grains were placed in a climatic chamber whose temperatures were 20, 30, 40, and 50 ± 1 °C combined with a relative humidity of 30, 40, 50, 70, and 90 ± 3%. Although in the desorption process, damaged grains had a lower differential enthalpy compared with the control, the reverse behavior was observed in the adsorption process. Mechanical damage caused the formation of a greater number of available adsorption sites, resulting in higher differential entropy values in adsorption and lower values in desorption compared with the control. The mechanical damage had no effect on the Gibbs free energy.Cinética de sorção de água de grãos de feijão danificado: Propriedades termodinâmicas R E S U M OObjetivou-se determinar as propriedades termodinâmicas de grãos de feijão danificados. Foram utilizados grãos com teor de água inicial de 53,85% (b.s.); parte dos grãos foi utilizada para se obter as isotermas de dessorção, enquanto que a outra foi submetida a secagem até o teor de água de 5,26% (b.s.), para que a mesma fosse submetida ao processo de adsorção. Para a indução da danificação foi utilizado um Stein Breakage Tester. Para obter o teor de água de equilíbrio, os grãos foram colocados em câmara climática cujas temperaturas foram de 20, 30, 40 e 50 ± 1 ºC combinadas com umidades relativas de 30, 40, 50, 70 e 90 ± 3%. Na dessorção, os grãos danificados apresentaram menor entalpia diferencial quando comparados com a testemunha enquanto o inverso foi observado na adsorção. A danificação mecânica provocou a formação de um número maior de sítios disponíveis de sorção, resultando em maiores valores de entropia diferencial na adsorção e menores valores na dessorção quando comparados com a testemunha. A danificação mecânica não teve efeito sobre a energia livre de Gibbs.

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“…La cinética de absorción de agua ha sido estudiada en la hidratación de alimentos como fríjol común [15], garbanzo [16], arroz rojo [17] y mandioca [18]; y materiales fibrosos como cáscara de coco [19] y Raffia vinífera con potencial para la construcción. Los modelos cinéticos más utilizados para explicar la cinética de absorción de agua en productos alimentarios son los modelos empíricos, entre los que se destacan los modelos de Pilosof et al [20], Singh y Kulshrestha [21], Peleg [22] y exponencial.…”

Section: Introductionunclassified