Mathematical modelling of drying characteristics of medical plants in a vacuum heat pump dryer

Dikmen, Erkan; Ayaz, Mahir; Kovacı, Tuğba; Şahin, Arzu Şencan

doi:10.1080/01430750.2017.1423383

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…The increase in air-drying temperature causes the movement of water molecules and an increase in the partial pressure of water vapor in the product, which promotes a reduction in the water content and water activity (a w ) [ 9 ]. The free water content is reduced to levels that can ensure a decrease in microbiological activity and enzymatic degradation, contributing to an increase in the shelf life of the product, in addition to favorably minimizing the packaging and transportation of the product, due to the reduction in volume [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…In the drying of aromatic plants, mathematical modeling predicts the drying behavior and can help in the definition of conditions for the process, capable of guaranteeing the preservation of the characteristics of the product, as well as a high efficiency for the drying [ 11 , 13 ]. Semi-theoretical models are the most used to describe the drying phenomenon.…”

Section: Introductionmentioning

confidence: 99%

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Convective Drying of Purple Basil (Ocimum basilicum L.) Leaves and Stability of Chlorophyll and Phenolic Compounds during the Process

Chaves

Araújo

Pena

2022

Plants

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This study evaluated the effect of convective drying on the degradation of color and phenolic compounds of purple basil (Ocimum basilicum L.) leaves, and the hygroscopic behavior of dried leaves. The fresh leaves underwent drying at 40 °C, 50 °C, 60 °C, and 70 °C. Degradation of chlorophyll, flavonoids, and phenolic compounds were evaluated during drying and the hygroscopicity was evaluated through the moisture sorption isotherms. The drying mathematical modeling and the moisture sorption data were performed. The effective diffusivity for the drying increased from 4.93 × 10−10 m2/s at 40 °C to 18.96 × 10−10 m2/s at 70 °C, and the activation energy value (39.30 kJ/mol) showed that the leaves present temperature sensibility. The leaves dried at 40 °C had less degradation of phenolic compounds and color variation, but the drying process was too slow for practical purposes. Modified Page, Diffusion Approximation, and Verna models had excellent accuracy in drying kinetics. The isotherms showed that, in environments with relative humidity above 50%, the purple basil leaves are more susceptible to water gain, and at 8.83 g H2O/100 g db moisture, it guarantees the microbiological stability of the dried leaves. The Oswin model was the most suitable for estimating the moisture sorption isotherms of the dried leaves.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Convective Drying of Purple Basil (Ocimum basilicum L.) Leaves and Stability of Chlorophyll and Phenolic Compounds during the Process

Chaves

Araújo

Pena

2022

Plants

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Section: Introductionmentioning

confidence: 99%

“…The leaves of aromatic plants are quite perishable products due to their high moisture content. Drying is an appropriate process to extend their shelf life and guarantee safety (Dikmen et al, 2018). The drying is a complex process that can cause changes in heat and mass transfer mechanisms as well as changes in product quality.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of heat mass performances for freeze drying of mint leaves

Kovacı

Dikmen

Şahin

2022

Food Processing Preservation

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Mint leaves are one of the most used medicinal and aromatic plants in the world, having a wide range of minerals and vitamins. It is necessary to prevent nutrient content and quality loss during the drying of the leaves. This study aimed to perform the drying of mint leaves and to experimentally specified the effective diffusion coefficient, activation energy, and heat and mass transfer coefficients values throughout the drying process. Mint leaves were dried using a laboratory‐scale dryer with three different drying temperatures (30, 40, and 50°C) and three different chamber pressures (50, 60, and 70 kPa). As a result, heat transfer coefficients varied from 0.3347 to 0.3353 W/m2K, and mass transfer coefficients varied from 3.33 × 10−10 to 2.27 × 10−9 m/s for different drying conditions. The effective moisture diffusivity during drying varied from 5.01 × 10−14 to 4.80 × 10−13 m2/s. The activation energy for mint leaves during drying varied from 79.07 to 76.44 kJ/mol at different drying temperatures. Practical applications Drying is an energy‐intensive process that involves simultaneous heat and mass transfer. In this study, the heat and mass transfer coefficients of mint leaves at different drying temperatures and pressures were studied. In order to optimize the drying process, the heat and mass parameters of the product must be fully understood. Understanding these parameters can easily provide a basis for designing dryers with the best energy saving.

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“…Dikmen et al investigated the drying characteristics of fresh parsley, sweet basil, and dill leave in freeze-drying at different temperatures. The best models were the Henderson and Pabis model for dill, the two-term model for parsley, and the logarithmic model for sweet basil [11]. Çelen et al carried out modelling of drying behaviour using microwave conveyor dryer assisted solar energy [12].…”

Section: Introductionmentioning

confidence: 99%

Drying Behaviors of Mint Leaves in Vacuum Freeze Drying

Kovacı

Dikmen

Şahin

2020

El-Cezeri Fen Ve Mühendislik Dergisi

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In this study, the drying behaviour of mint, which is one of the medicinal plants in freeze-drying, was investigated. The products were dried at three different temperatures (40, 50, 60 o C) and three different pressures (30, 50, 80 kPa) in a freeze-drying system designed as a prototype. Drying time is decreased with increasing cabin pressure. Optimal working conditions in the freeze-drying of mint leaves were determined as 30 kPa chamber pressure and 50°C drying temperature. Four thin layer drying models, namely Newton model, Tow term exponential model, Logarithmic model, and Wang and Singh model are tested to predict the drying behaviour. The Wang and Singh model has presented the best prediction that has an R 2 value of 0.99687.

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Mathematical modelling of drying characteristics of medical plants in a vacuum heat pump dryer

Cited by 11 publications

References 22 publications

Convective Drying of Purple Basil (Ocimum basilicum L.) Leaves and Stability of Chlorophyll and Phenolic Compounds during the Process

Convective Drying of Purple Basil (Ocimum basilicum L.) Leaves and Stability of Chlorophyll and Phenolic Compounds during the Process

Evaluation of heat mass performances for freeze drying of mint leaves

Drying Behaviors of Mint Leaves in Vacuum Freeze Drying

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