Optimisation of onion bulb curing using a heat and mass transfer model

Zewdie, Tewodros A.; Delele, Mulugeta Admasu; Fanta, Solomon Workneh; Alemayehu, Melkamu; Alemayehu, Getachew; Adgo, Enyew; Nyssen, Jan; Verboven, Pieter; Nicolaı̈, Bart

doi:10.1016/j.biosystemseng.2021.12.009

Cited by 5 publications

(14 citation statements)

References 28 publications

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“…The result revealed that a drying temperature difference of up to 10 • C did not have a significant effect on all investigated quality attributes. Moreover, a coupled heat and mass transfer model was developed for optimizing the curing process as well as to assess the influence of curing parameters on the desirable level of curing (Zewdie et al, 2022). From the result of this study, it was observed that relative humidity had a more pronounced effect than temperature.…”

Section: Temperature and Relative Humidity Distributionmentioning

confidence: 98%

“…The overall mass transfer coefficient in Equation ( 9) is composed of skin and external mass transfer coefficients and was obtained using the following equation (Zewdie et al, 2022):…”

Section: Model Equations and Boundary Conditionsmentioning

confidence: 99%

“…The value of h m,s is calculated from a Nusselt correlation for stacked spheres and the Lewis analogy. The details about the calculation of h m,s can be found in Zewdie et al (2022). Hence, the relative importance of the external and skin mass transfer coefficient could be evaluated using a mass transfer Biot number analysis from high to a low moisture content of the skin.…”

Section: Model Equations and Boundary Conditionsmentioning

confidence: 99%

“…The unknown function f, which relates skin mass transfer coefficient to water vapor concentration, was determined by calculating skin permeability from moisture-dependent effective moisture diffusivity at various water vapor concentrations from our previous work (Zewdie et al, 2022), and then by curve fitting the skin permeability vs water vapor concentration plot using the Matlab curve fitting toolbox (The MathWorks, Inc., Natick, MA, USA). The following exponential expression of skin permeability as a function of water vapor concentration provided a very good fit:…”

Section: Model Equations and Boundary Conditionsmentioning

confidence: 99%

“…In a previous study, a heat and mass transfer model for the curing process of a single onion bulb was developed to evaluate the effect of curing conditions on set curing criteria. The result revealed that achieving a desirable level of curing for longterm storage of onions depends on curing process conditions (curing relative humidity and duration) (Zewdie et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Design and evaluation of a prototype solar energy driven onion curing system using CFD modeling

Zewdie

Delele

Fanta

et al. 2022

Front. Sustain. Food Syst.

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In developing countries like Ethiopia, where the time of harvesting coincides with the dry season, farmers cure onion bulbs naturally on the field. Field curing generally takes longer than artificial curing and results in more losses and reduced quality of the bulbs due to increased risks for infestations and uncontrolled suboptimal drying conditions. Large-scale artificial curing systems are expensive and electrical energy supply is limited in rural areas. A CFD model was employed to design an alternative and sustainable onion curing system that can be deployed on the field in rural areas. The developed CFD model was validated by comparing the predicted air velocity, temperature, and mass loss to measured values on a prototype curing system operated on a field in Ethiopia. A good agreement between the model and experimental value was observed for the time profiles of temperature at different positions in the bulk of onions during curing, expressed by a root mean square error of 1.1°C in the temperature range from 28 to 47°C, 0.16 m s−1 in the velocity range from 0.1 to 2.5 m s−1, and 0.565% for the mass loss that ranged up to 6.35%. The developed model was used to assess the air velocity, temperature, and relative humidity distribution in order to get an insight into the uniformity of curing of onion bulbs using the develop alternative curing system. For all of the examined curing durations, the drying air temperature variation inside 80% of the porous medium was < 3°C. In the remaining 20% of the porous medium, a temperature variation of up to 6°C was observed. Thus, the newly designed and developed curing system was found to cure the onion bulbs uniformly. Moreover, its performance was evaluated experimentally and the onions were cured to a desirable level of curing for long-term storage within a total curing duration of 48 h. It is vital to consider bulb shrinkage, particularly in the neck, in order to further improve the model mass loss prediction.

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Section: Temperature and Relative Humidity Distributionmentioning

confidence: 98%

“…The overall mass transfer coefficient in Equation ( 9) is composed of skin and external mass transfer coefficients and was obtained using the following equation (Zewdie et al, 2022):…”

Section: Model Equations and Boundary Conditionsmentioning

confidence: 99%

Section: Model Equations and Boundary Conditionsmentioning

confidence: 99%

Section: Model Equations and Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design and evaluation of a prototype solar energy driven onion curing system using CFD modeling

Zewdie

Delele

Fanta

et al. 2022

Front. Sustain. Food Syst.

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A comprehensive review on recent advances in postharvest treatment, storage, and quality evaluation of onion (Allium cepa): Current status, and challenges

Kiran,

Aradwad,

T. V.

et al. 2024

Future Postharvest and Food

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Onion is an important economical and nutritional vegetable crop having a global demand. However, the long‐term storage and availability of quality produce during off seasons remain a constraint. The intricate process of quality degradation in onions, both pre and postharvest, is influenced by internal factors and storage conditions. To preserve the postharvest quality and prolong the shelf life of onions, effective postharvest technologies incorporating quality assessment and preservation treatments are crucial. This paper delves into the key factors associated with crop quality, postharvest treatments, and storage, providing a comprehensive understanding of their cause‐effect relationships. The primary objective of this review is to shed light on diverse postharvest treatments, storage conditions, and structures, along with their effects on the physical, chemical, and biochemical aspects of onions. Additionally, the study explores destructive and non‐destructive assessment technologies to evaluate the quality of onions. Storage and marketability is intricately tied to the advancement of appropriate technology aimed at minimizing losses during various stages of harvesting and storage conditions. This review serves as a preliminary document that can assist in exploring critical factors and advancing technologies to enhance the shelf life and quality of onions, bridging the gap between traditional methods and promising advancements.

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On Methods for Determining the Moisture Content of Materials in a Confined Medium

Parfentieva

Panfilova

Коновалов

et al. 2023

Lecture Notes in Networks and Systems

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Optimisation of onion bulb curing using a heat and mass transfer model

Cited by 5 publications

References 28 publications

Design and evaluation of a prototype solar energy driven onion curing system using CFD modeling

Design and evaluation of a prototype solar energy driven onion curing system using CFD modeling

A comprehensive review on recent advances in postharvest treatment, storage, and quality evaluation of onion (Allium cepa): Current status, and challenges

On Methods for Determining the Moisture Content of Materials in a Confined Medium

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