Equilibrium moisture content and sorption isosteric heats of five wheat varieties in China

Li, Xingjun; Zhi-yang, Cao; Wei, Zhiyan; Feng, Qian; Wang, Jinshui

doi:10.1016/j.jspr.2010.10.001

Cited by 51 publications

(32 citation statements)

References 19 publications

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“…In this study, the fitted MCPE isotherms of soft wheat slightly lied above those of hard wheat at the temperatures of 20 and 30 °C . The similar hygroscopic properties between hard and soft wheat might be due to the overall effects of hygroscopic properties of their respective protein and starch (Li et al, 2011). The reason for the similar hygroscopic properties between red and white wheat, as well as between winter and spring wheat, needs further study on microstructural or morphologic characteristic of different wheat varieties.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, we studied the moisture sorption data of some Chinese wheat varieties (one mixed, two hard, two soft wheats). By using six equations, the Brunauer-Emmett-Teller (BET), CCE, MCPE, MHE, MOE and SYE, it is found that these hard and soft wheat varieties show similar hygroscopic properties and sorption isosteric heats (Li et al, 2011). In the literature, few reports are about the hygroscopic properties and sorption isosteric heats between winter and spring wheat, as well as between red and white wheat.…”

Section: Introductionmentioning

confidence: 99%

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The Hygroscopic Properties and Sorption Isosteric Heats of Different Chinese Wheat Types

Li¹

2012

JFR

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The moisture sorption isotherm data of fourteen Chinese wheat varieties were determined using the static gravimetric method at five different temperatures (10, 20, 25, 30 and 35 °C ) and relative humidity ranging from 11.3 to 96%. Eight models, namely Brunauer-Emmett-Teller, CAE, Chen-Clayton, Modified-Chung-Pfost (MCPE), Modified-Henderson, Modified-Guggenheim-Anderson-deBoer, and Modified-Oswin and Strohman-Yoerger, were used to fit the sorption data. MCPE shows the best fitting results. A significant hysteresis effect was found between wheat desorption and adsorption isotherm at lower ERH, but the similar hygroscopic properties remained for different wheat types like hard vs. soft, red vs. white, and winter vs. spring, respectively. The experimental results show that the isosteric heats for both wheat adsorption and desorption, and all the sorption heats for different wheat types decrease rapidly with increasing seed moisture initially, however, after the moisture is more than 15% w.b. they decrease tardily with increasing moisture content. The isosteric heats of wheat desorption were considerably higher than those of adsorption below 17.5% m.c., but the similar sorption isosteric heats were found for wheat types like hard vs. soft, red vs. white, or winter vs. spring, respectively. It is concluded that the wheat grains from different types have similar hygroscopic properties and sorption isosteric heats and can be synchronously dealt with during physical control in storage.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Hygroscopic Properties and Sorption Isosteric Heats of Different Chinese Wheat Types

Li¹

2012

JFR

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“…Os modelos matemáticos obtidos na literatura e representativos da higroscopicidade de produtos agrícolas, utilizados neste trabalho, foram escolhidos em função da avaliação da temperatura e umidade relativa do ambiente, para a verificação do que melhor se ajusta à realidade empírica do produto, de maneira a melhor representar sua isoterma (QIAOFANG et al, 2013;BABETTO et al, 2011;LI et al, 2011;ACHARJEE et al, 2011;LAM et al, 2012;BROOKER et al, 1992). Os modelos utilizados estão presentes na Tabela 1.…”

Section: Methodsunclassified

“…O calor isostérico, também denominado calor de sorção ou entalpia de vaporização, é um parâmetro capaz de permitir a avaliação da demanda energética necessária aos processos de desidratação, secagem e queima de materiais biológicos, além de serem essenciais para a escolha da melhor estratégia de armazenamento (LI et al, 2011).…”

Section: Methodsunclassified

Determinação do equilíbrio higroscópico e do calor isostérico do bagaço de cana-de-açúcar

Teixeira¹,

Andrade²,

Espíndola³

et al. 2015

Eng. Agríc.

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RESUMO:Com o intuito de analisar a dinâmica de sorção e a energia necessária para a vaporização da água na desidratação do bagaço da cana-de-açúcar, o presente trabalho teve como objetivo a determinação de seu equilíbrio higroscópico e calor isostérico, a partir de diferentes condições controladas de temperatura (20; 40; 55 e 70 ºC) e umidade relativa do ar (10; 12; 17; 18; 30; 40; 45; 50; 60 e 85%), assim como avaliar, entre diversos modelos descritos na literatura, o que melhor represente o comportamento de sorção. Como resultado, foi verificado que o modelo que melhor se ajustou aos dados empíricos do processo de sorção do bagaço de cana-de-açúcar foi o Modelo de Henderson Modificado, com coeficiente de determinação de 0,972, enquanto o calor isostérico integral de dessorção variou de 2524,09 a 2951,95 kJ kg -1 , para os teores de água de equilíbrio de 0,014 a 0,170 b.s., respectivamente. PALAVRAS-CHAVE:bagaço de cana-de-açúcar; equilíbrio higroscópico; calor isostérico. HYGROCOPIC EQUILIBRIUM AND ISOSTERIC HEAT OF SUGARCANE BAGASSABSTRACT: This study aimed to determine the hygroscopic equilibrium and isosteric heat of sugarcane bagasse to evaluate sorption dynamics and the required energy to vaporize water in the bagasse dehydration. The reaction was assessed at different controlled conditions of temperature (20, 40, 55 and 70 ºC) and air relative humidity (10, 12, 17, 18, 30, 40, 45, 50, 60 and 85%), as well as testing various models described in the literature to identify the condition that better represents sorption behavior. As a result, we found that the model that best fit empirical data of sugarcane bagasse sorption was the modified Henderson with determination coefficient of 0.972; while the integral isosteric heat of desorption ranged from 2,524.09 to 2,951.95 kJ kg -1 , for all water contents and equilibrium of 0.014 until 0.170 bs, respectively.

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“…The changes in sample moisture with time was determinate by the static gravimetric method [6] with two saturated salt (NaNO 2 and K 2 CrO 4 ) solutions and distilled water to maintain constant vapor pressure at each of five constant temperatures (10,20,25,30, and 35°C) under 65%, 86%, and 100% RH, respectively. Three wide mouth glass bottles (250 mL) each containing 65 mL salt solution or distilled water were kept in one temperature controlled cabinet to maintain three groups of different RH levels ranging from 65% to 100%.…”

Section: Determination Of Changes In Milled Rice Kernel Moisture Withmentioning

confidence: 99%

Moisture Adsorption Rate and Effective Diffusivity in Chinese Milled Rice

Han¹,

Wang²,

ZiDan³

et al. 2017

dtcse

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Abstract. Four varieties of Chinese milled rice samples with 11.90-15.56% initial moisture content (IMC, wet basis) were used to determine the rate of moisture adsorption using the gravimetric method at 10, 20, 25, 30, and 35°C under 65%, 86%, and 100% relative humidity (RH), respectively. A moisture diffusion equation was modified to fit the relationship between the moisture ratio (MR) of samples and exposure time. In the range of 65% to 100% RH, the lower IMC of milled rice samples corresponded to higher moisture adsorption rate at temperatures of 10 to 35°C. The moisture adsorption rate of samples increased with an increasing temperature. The moisture sorption rate of samples with the same IMC increased with increasing RH at certain temperatures. A single milled rice kernel was geometrically considered a finite homogeneous cylinder shape, and the analytical solution of the partial differential equation of moisture diffusion was given. The effective moisture diffusivity was calculated using a slope method by plotting the experimental data in terms of ln (MR) versus rewetting time. In the range of 10-35°C, the effective moisture adsorption diffusivity of milled rice kernels with normal moisture was 4.321×10 -9 -1.117×10 -7 m 2 h -1 . For the same IMC, the effective moisture diffusivity of milled kernels tended to increase with increases in surrounding temperature at certain relative humidity levels, but decreased with an increase in RH at certain temperatures. It was concluded that the milled rice samples from different types had similar effective moisture diffusivity when similar IMC was given.

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Equilibrium moisture content and sorption isosteric heats of five wheat varieties in China

Cited by 51 publications

References 19 publications

The Hygroscopic Properties and Sorption Isosteric Heats of Different Chinese Wheat Types

The Hygroscopic Properties and Sorption Isosteric Heats of Different Chinese Wheat Types

Determinação do equilíbrio higroscópico e do calor isostérico do bagaço de cana-de-açúcar

Moisture Adsorption Rate and Effective Diffusivity in Chinese Milled Rice

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