Effect of Temperature Distribution on Predicting Quality Of Microwave Dehydrated Food

Joardder, Mohammad Uzzal Hossain; Karim, Azharul; Kumar, Chandan

doi:10.15282/jmes.5.2013.2.0053

Cited by 40 publications

(21 citation statements)

References 17 publications

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“…Water is vaporized very fast, which results in an increase in the DR, but the amount of vapor produced is too small to significantly raise the temperature of the body being dried. A similar phenomenon was observed by Joardder, Karim, and Kumar () during the microwave drying of apples. Measured with a thermal camera, the temperatures of the samples fluctuated during the drying process, which was explained by the nonhomogenous microwave field, changes in the water content, and temperature redistribution within the sample.…”

Section: Resultssupporting

confidence: 86%

The microwave‐assisted convective drying of kale (Brassica oleracea L. var. sabellica L.) using continuous and changeable power radiation

Mierzwa

2019

J Food Process Engineering

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Convective drying is one of the most commonly used methods of food dehydration. This technique allows highly perishable products to be preserved; however, it is simultaneously time‐consuming, energy‐consuming and has a negative impact on the products' quality. In order to eliminate these drawbacks alternative drying methods have been sought. This article concerns the microwave‐assisted convective drying of kale. Eight different drying processes were tested. The influence of both continuous and changeable application of microwaves on process kinetics (drying rate), energy consumption, and quality of product (color and ascorbic acid retention) was analyzed. Additionally, four thin‐layer drying models were used to approximate the experimental data and an effective diffusion coefficient was calculated. It was found that the continuous application of microwaves positively influenced kinetics and energy consumption but may have an adverse effect on the products' quality. In contrast, intermittent‐hybrid schedules were characterized by smaller kinetics advantages but a visibly better quality of product. Practical applications In the face of current environmental problems (reduction of CO2 emissions) and increasing prices for electricity, the high energy consumption in convective processes is encouraging the search for alternative methods of drying food products that are prone to spoilage. Additionally, consumer awareness is growing, which is increasing the demand for high‐quality, safe, food products. This work concerns the optimization of existing technology and the development of new technologies for food drying using microwaves. Microwave radiation is an effective source of energy that allows a significant reduction in drying time and energy consumption; but it can have a negative impact on product quality. The proposed solution is the intermittent use of microwaves; but the matter is not simple because the dielectric properties of food depend on many factors (moisture content, composition, temperature, etc.), which makes the effects of microwave drying difficult to predict. Thus, all research on this topic is valuable.

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Section: Resultssupporting

confidence: 86%

The microwave‐assisted convective drying of kale (Brassica oleracea L. var. sabellica L.) using continuous and changeable power radiation

Mierzwa

2019

J Food Process Engineering

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“…There was a problem, however, with the continuous application of microwaves in the drying process, as high product temperatures and uneven heating resulted [3] . As noted above, high drying temperatures can cause quality degradation in heat sensitive materials, such as fruits and vegetables [5,6] . This problem can potentially be overcome by applying microwave power intermittently.…”

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confidence: 98%

Mathematical model for intermittent microwave convective drying of food materials

et al. 2015

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Intermittent microwave convective drying (IMCD) is an advanced technology that improves both energy efficiency and food quality in drying. Modelling of IMCD is essential to understand the physics of this advanced drying process and to optimize the microwave power level and intermittency during drying. However, there is still a lack of modelling studies dedicated to IMCD. In this study, a mathematical model for IMCD was developed and validated with experimental data. The model showed that the interior temperature of the material was higher than the surface in IMCD, and that the temperatures fluctuated and redistributed due to the intermittency of the microwave power. This redistribution of temperature could significantly contribute to the improvement of product quality during IMCD. Limitations when using Lambert's Law for microwave heat generation were identified and discussed.

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“…These variations which could be as a result of the nonuniform temperature distribution within the sweet potato slice core may affect the quality of sweet potato during drying. In addition, the nonuniform temperature distribution predicted by the developed model is as a result of the infrared heat flux based on Lambert Law (Joardder, Karim, & Kumar, ; Kumar et al, ; Yang & Gunasekaran, ). As such, a novel‐controlled infrared drying system at optimum drying conditions and an improved infrared heat flux model based on Maxwell equation are required.…”

Section: Resultsmentioning

confidence: 99%

“…Overall, the model suggests that there are large spatial variations in the moisture content within the sweet potato slice core during the drying process. These variations which could be as a result of the nonuniform temperature distribution within the sweet potato Lambert Law (Joardder, Karim, & Kumar, 2013;Kumar et al, 2017;Yang & Gunasekaran, 2004). As such, a novel-controlled infrared drying system at optimum drying conditions and an improved infrared heat flux model based on Maxwell equation are required.…”

Section: Fundamental Infrared Drying Behavior Of Sweet Potatomentioning

confidence: 99%

Numerical modeling of radiative heat and mass transfer for sweet potato during drying

Onwude

Hashim

Abdan

et al. 2018

J Food Process Preserv

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In this study, a numerical model was developed to accurately describe the changes in moisture content and temperature distribution of sweet potato during infrared drying, with the consideration of shrinkage‐dependent diffusivity and evaporation phenomena. The couple heat and mass transfer and 2D axisymmetric simulations were done using COMSOL Multiphysics. The simulation results were further evaluated based on experimental data. Sensitivity analysis was also conducted and the effects of different simulation parameters on the drying process were presented. The results showed that the developed model considering shrinkage diffusivity and evaporation adequately described the drying process of sweet potato undergoing infrared drying. The mass transfer coefficient, heat transfer coefficient, shrinkage‐dependent diffusivity, and infrared heat energy greatly influenced the moisture distribution during the drying process of sweet potato. The temperature distribution during the infrared drying of sweet potato was highly sensitive to the infrared heating energy. Practical applications Sweet potato is a common industrial crop with numerous human benefits. Industrial drying of sweet potato using conventional methods is energy intense translating into higher production cost. Infrared drying has been reported to consume less amount of energy compared to other thermal drying processes. However, this drying method has also shown to affect the quality of dried product owning to its high and nonuniform temperature distribution. In this study, heat and mass transfer during infrared drying was analyzed and modeled. The simple model was able to predict the temperature and moisture distribution during drying. Consequently, the heat and mass transfer model will be useful in controlling and optimizing the infrared drying process and improve the final quality of sweet potato.

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Effect of Temperature Distribution on Predicting Quality Of Microwave Dehydrated Food

Cited by 40 publications

References 17 publications

The microwave‐assisted convective drying of kale (Brassica oleracea L. var. sabellica L.) using continuous and changeable power radiation

The microwave‐assisted convective drying of kale (Brassica oleracea L. var. sabellica L.) using continuous and changeable power radiation

Mathematical model for intermittent microwave convective drying of food materials

Numerical modeling of radiative heat and mass transfer for sweet potato during drying

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