Arrhenius activation energy for water diffusion during drying of tomato leathers: The concept of characteristic product temperature

Fiorentini, Cecilia; Demarchi, Silvana María; Ruiz, Natalia Andrea Quintero; Irigoyen, R. Martín Torrez; Giner, Sergio A.

doi:10.1016/j.biosystemseng.2015.02.004

Cited by 34 publications

(25 citation statements)

References 15 publications

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“…To determine the dependence of D eff on air temperature within Fick's second law or the anomalous diffusion model, ln( D eff ) was linearly correlated with the reciprocal of the absolute air temperature ( T ) by applying the Arrhenius model (Fiorentini, Demarchi, Quintero Ruiz, Torrez Irigoyen, & Giner, ):

\ln true(D_{eff} true) = \ln true(D_{0} true) - \frac{E_{a}}{R} true(\frac{1}{T} true)

where D 0 is the pre‐exponential factor of the Arrhenius equation (m 2 /s), E a is the activation energy (kJ/mol), R is the gas constant (kJ/mol K), and T is the absolute temperature (K).…”

Section: Methodsmentioning

confidence: 99%

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Anomalous diffusion based on fractional calculus approach applied to drying analysis of apple slices: The effects of relative humidity and temperature

Ramírez

Astorga

Núñez

et al. 2017

J Food Process Engineering

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The objective of this research was to evaluate the diffusion mechanism based on Fick's second law and anomalous diffusion modifying the drying operating conditions temperature (T) and relative humidity (RH) on apple slices (cv. Granny smith). Drying was performed at 30 °C, 40 °C, 50 °C and 30%, 50%, 70%RH based on a 32 experimental design. The drying curves were analyzed to determine the effective diffusion (Deff) using two methods: Fick's second law and anomalous diffusion model based on fractional calculus approach. Our results showed that the anomalous diffusion mechanism fit the experimental data better and revealed a super‐diffusive behavior (α > 1). Therefore, Deff values were estimated using the anomalous diffusion model with α = 1.735. With respect to the use of anomalous diffusion model solution based on fractional calculus at different operations conditions allow to get better fitting of drying data than second Fick's law model, even keeping the Arrhenius behavior of Deff with temperature. Practical applications Diffusion process is typically analyzed using models based on Fick's second law. However, several assumptions inherent in Fick's second law are not fulfilled in food materials (e.g., structural heterogeneity). In addition, Fick's second law does not consider structural variations during the drying process, and it is well known that fruits such as apples experience significant structural changes during drying. Fractional calculus is a tool for mathematically representing the anomalous diffusion of solutes whose movements can be faster or slower than postulated in Fick's second law due to food structure. In general, with second Fick's law model not good fitting to data are obtained, therefore the prediction capacity of the model is limited. Based on this, anomalous diffusion solution based on fractional calculus was applied. The results showed good fit the data to the model, and also by the time exponent (α) is possible to identify the kind of diffusion process.

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\ln true(D_{eff} true) = \ln true(D_{0} true) - \frac{E_{a}}{R} true(\frac{1}{T} true)

where D 0 is the pre‐exponential factor of the Arrhenius equation (m 2 /s), E a is the activation energy (kJ/mol), R is the gas constant (kJ/mol K), and T is the absolute temperature (K).…”

Section: Methodsmentioning

confidence: 99%

“…To determine the dependence of D eff on air temperature within Fick's second law or the anomalous diffusion model, ln(D eff ) was linearly cor-related with the reciprocal of the absolute air temperature (T) by applying the Arrhenius model (Fiorentini, Demarchi, Quintero Ruiz, Torrez Irigoyen, & Giner, 2015):…”

Section: Temperature Dependence Of D Effmentioning

confidence: 99%

Anomalous diffusion based on fractional calculus approach applied to drying analysis of apple slices: The effects of relative humidity and temperature

Ramírez

Astorga

Núñez

et al. 2017

J Food Process Engineering

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“…The Arrhenius equation (Equation 11) was applied for evaluation of the effect of temperature on the effective diffusion coefficient. From its structure, we could observe that the relation of ln ( D eff ) as a function of the inverse of temperature (T ‐1 ) provides a line whose angular coefficient allowed estimating the value of activation energy ( E a ) (Fiorentini, Demarchi, Quintero Ruiz, Torrez Irigoyen, & Giner, ; Torrez Irigoyen & Giner, ).

D_{eff} = D_{o} \exp (\frac{- E_{a}}{RT})

…”

Section: Methodsmentioning

confidence: 99%

Kinetic and physicochemical properties of drying‐ozonation process on wheat grain

Granella

Bechlin

Christ

et al. 2019

J Food Process Preserv

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This study dealt about the thermal and kinetic characteristics of wheat during the drying‐ozonation process (DOP) needed for planning better drying methods that preserve desirable characteristics and minimize energy consumption. For this, ozone gas was applied with the drying air in different conditions, 15 and 45 min ozonation times and drying temperatures at 30, 40, and 50°C on wheat grains. During the drying, moisture ratio reduced, and the Midili model performed the best fit to experimental data. Activation energy to DOP was 30.40 kJ/mol (15 min O3) and 27.21 kJ/mol (45 min O3), being lesser that reference drying of 32.18 kJ/mol. DOP did not influence the ash, protein, lipid, and starch content of exposed wheat grains for 15 min to ozone. However, when the grains were exposed to 45 min of ozone, regardless of the drying temperature used, there was a significant reduction of the starch content. Thus, the results demonstrated an alternative to obtaining energy efficiency during the postharvest stages and preservation of grains quality. Practical applications Food ozonation is a process that ensures adequate sanitation without toxic waste accumulation. The use of ozone into the drying air is a modern method that can contribute to energy improvement and product quality maintenance in agro‐industries. Knowledge of drying‐ozonation process and its kinetic properties as functions of temperature, efficient diffusion of moisture and activation energy are essential for understanding the process, designing dryers and reduction of energy consumption.

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“…Com base em Fiorentini et al (2015), a nova estratégia adotada para melhorar o ajuste dos modelos consistiu em dividir os dados de umidade em função do tempo em duas zonas de secagem, zona seca e zona úmida, e ajustar o modelo difusivo reparametrizado para cada zona. Para a definição de cada zona, determinou-se o tempo crítico considerando duas abordagens diferentes.…”

Section: Ajuste Dos Modelosunclassified

Secagem De Granulado Mineral: Exploração Da Equação De Arrhenius Como Ferramenta Para Estimar a Energia De Ativação E a Difusividade Efetiva

Souza¹,

Perazzini²

2017

Blucher Chemical Engineering Proceedings

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RESUMO -No presente trabalho, é apresentado um estudo da cinética de secagem de um granulado mineral poroso. O material foi caracterizado por meio da determinação de suas principais propriedades físicas e estruturais. O modelo difusivo reparametrizado foi utilizado para ajustar dados experimentais de umidade em função do tempo. Como as primeiras propostas de ajuste não foram satisfatórias, uma nova estratégia foi adotada, realizando-se novos estudos de simulação para duas diferentes zonas de secagem, denominadas: zona seca e zona úmida. Com base nos resultados obtidos, verificou-se que a energia de ativação é maior para a zona seca e menor pra a zona úmida, enquanto que o inverso foi observado para a difusividade efetiva. INTRODUÇÃOA secagem é uma das operações unitárias mais utilizadas atualmente, fazendo parte dos mais diversos processos industriais. Entretanto, para que a secagem ocorra, são necessárias para alguns materiais altas temperaturas e elevada velocidade de ar, o que acarreta custos operacionais e energéticos muito altos, aumentando consideravelmente o valor do produto final, podendo até inviabilizar sua comercialização. Assim, para que a secagem seja economicamente viável é preciso otimizar o processo, estudando os mecanismos de transporte envolvidos e as características do material a ser seco. Apesar de ser um processo já consolidado e muito utilizado em indústrias, a secagem raramente é operada em sua máxima eficiência. Estudos de cinética de secagem, por sua vez, auxiliariam na otimização do processo, minimizando o consumo de insumos e os gastos energéticos envolvidos. Esta pesquisa teve como objetivo analisar a cinética de secagem de um granulado mineral, que por apresentar excelente porosidade e elevada capacidade de adsorção, possui potencial para ser considerado uma ótima alternativa para a composição do recheio de colunas de adsorção, por exemplo. MATERIAIS E MÉTODOS Material ParticuladoO material estudado é um granulado mineral branco composto de gesso, ligantes e fibras minerais, inerte e atóxico que possui o núcleo poroso, fazendo com que a sua

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Arrhenius activation energy for water diffusion during drying of tomato leathers: The concept of characteristic product temperature

Cited by 34 publications

References 15 publications

Anomalous diffusion based on fractional calculus approach applied to drying analysis of apple slices: The effects of relative humidity and temperature

Anomalous diffusion based on fractional calculus approach applied to drying analysis of apple slices: The effects of relative humidity and temperature

Kinetic and physicochemical properties of drying‐ozonation process on wheat grain

Secagem De Granulado Mineral: Exploração Da Equação De Arrhenius Como Ferramenta Para Estimar a Energia De Ativação E a Difusividade Efetiva

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