scholarly journals Identifying in-silico how microstructural changes in cellular fruit affect the drying kinetics

2020 ◽  
Author(s):  
Kevin Prawiranto ◽  
Jan Carmeliet ◽  
Thijs Defraeye
Keyword(s):  
Relative Humidity ◽  
Apple Fruit ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Rate ◽  
Free Shrinkage ◽  
Microstructural Changes ◽  
Cellular Dehydration ◽  
Microscale Model ◽  
The Impact

Convective drying of fruits leads to microstructural changes within the material as a result of moisture removal. In this study, an upscaling approach is developed to understand and identify the relation between the drying kinetics and the resulting microstructural changes of apple fruit, including shrinkage of cells without membrane breakage (free shrinkage) and with membrane breakage (lysis). First, the effective permeability is computed from a microscale model as a function of the water potential. Both temperature dependency and microstructural changes during drying are modeled. The microscale simulation shows that lysis, which can be induced using various pretreatment processes, enhances the tissue permeability up to four times compared to the free shrinkage of the cells. Second, via upscaling, macroscale modeling is used to quantify the impact of these microstructural changes in the fruit drying kinetics. We identify the formation of a barrier layer for water transport during drying, with much lower permeability, at the tissue surface. The permeability of this layer strongly depends on the dehydration mechanism. We also quantified how inducing lysis or modifying the drying conditions, such as airspeed and relative humidity, can accelerate the drying rate. We found that inducing lysis is more effective in reducing the drying rate (up to 26%) than increasing the airspeed from 1 to 5 m/s or decreasing the relative humidity from 30% to 10%. This study quantified the need for including cellular dehydration mechanisms in understanding fruit drying processes and provided insight at a spatial resolution that experiments almost cannot reach.

scholarly journals Drying Kinetics Comparison of Methylcellulose Gel Versus Mango Fruit in Forced Convective Drying With and Without Electrohydrodynamic Enhancement

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Erik Bardy ◽  
Sabrine Manai ◽  
Michel Havet ◽  
Olivier Rouaud
Keyword(s):  
Moisture Content ◽  
Food Product ◽  
Drying Kinetics ◽  
Area Measurement ◽  
Convective Drying ◽  
Drying Rate ◽  
Wire Electrode ◽  
Exergetic Efficiency ◽  
Mango Fruit ◽  
Drying Time

Electrohydrodynamic convective drying (EHD drying) is a novel drying method used to enhance forced convection drying (FC drying) by using a wire-electrode to create an electrostatic field. In a previous study, the efficiency of EHD drying (using three different wire-electrode configurations) was compared to classical FC drying by measuring the drying rate of methylcellulose gel. Efficiency was quantified in terms of exergy (transient exergetic efficiency) through the use of a proposed model. In that previous study, it was stated that methylcellulose gel can be used to simulate a food product and can be controlled to a predetermined moisture content. The purpose of this current work was to compare how methylcellulose gel compares to a real food product (mango fruit) in terms of drying kinetics for both EHD and FC drying. Drying kinetics were quantified in terms of a per unit area measurement of the exergetic efficiency, exergy supplied and used, drying rate, and total drying time to reach a moisture content of 50%. Initial results show that for both EHD and FC drying, methylcellulose gel and mango fruit exhibit similar drying kinetics.

scholarly journals Evaluation of a Moisture Diffusion Model for Analyzing the Convective Drying Kinetics of Lavandula x allardii Leaves

Computation ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 141
Author(s):  
Vasileios Chasiotis ◽  
Dimitrios Tzempelikos ◽  
Andronikos Filios
Keyword(s):  
Diffusion Model ◽  
Moisture Transfer ◽  
Variable Temperature ◽  
Moisture Diffusion ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Water Evaporation ◽  
Drying Rate ◽  
Computationally Efficient ◽  
Kinetics Of

In the present case study, a moisture diffusion model is developed to simulate the drying kinetics of Lavandula x allardii leaves for non-stationary convective drying regimes. Increasing temperature profiles are applied over the drying duration and the influence of temperature advancing rates on the moisture removal and the drying rate is investigated. The model assumes a one-dimensional moisture transfer under transient conditions, which occurs from the leaf center to the surface by liquid diffusion due to the concentration gradient developed by the surface water evaporation caused by the difference of water vapor partial pressure between the drying medium and the leaf surface. A numerical solution of Fick’s 2nd law is obtained by an in-house code using the finite volume method, including shrinkage and a variable temperature-dependent effective moisture diffusion coefficient. The numerical results have been validated against experimental data for selected cases using statistical indices and the predicted dehydration curves presented a good agreement for the higher temperature advancing rates. The examined modeling approach was found stable and can output, in a computationally efficient way, the temporal changes of moisture and drying rate. Thus, the present model could be used for engineering applications involving the design, optimization and development of drying equipment and drying schedules for the examined type of non-stationary drying patterns.

Microwave- and ultrasound-assisted convective drying of raspberries: Drying kinetics and microstructural changes

2018 ◽  
Vol 37 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Justyna Szadzińska ◽  
Joanna Łechtańska ◽  
Reihaneh Pashminehazar ◽  
Abdolreza Kharaghani ◽  
Evangelos Tsotsas
Keyword(s):  
Drying Kinetics ◽  
Convective Drying ◽  
Microstructural Changes ◽  
Ultrasound Assisted

The Impact of the Pre-Treatment in Ethanol Solution on the Drying Kinetics and Selected Properties of Convective Dried Apples

2019 ◽  
Vol 16 (1-2) ◽  
Author(s):  
Joanna Zubernik ◽  
Magdalena Dadan ◽  
Joanna Cichowska ◽  
Dorota Witrowa-Rajchert
Keyword(s):  
Ethanol Solution ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Total Phenolic ◽  
Prolonged Storage ◽  
Drying Time ◽  
Pre Treatment ◽  
The One ◽  
The Impact

AbstractThe aim of this study was to investigate the effects of pre-treatment in ethanol solution carried out in variable time with and without ultrasound (US) assistance on convective drying kinetics, total phenolic content (TPC) and hygroscopicity of an apple. The drying time after immersion in ethanol solution was shorter up to 13.4 (without US) and 18.3 % (with US) in comparison to intact slices. The most appropriate model that described kinetics of drying was the one proposed by Sledz et al. Drying of the untreated apple resulted in a decrease of the TPC by 18 %, compared with raw apples and the pre-treatment led to further losses. The tissue after ethanol pre-treatment was less hygroscopic, which proves the possibility to maintain a characteristic texture of the dried apple with prolonged storage stability. The best quality of dried apples was obtained after 1 min of ethanolic pre-treatment with US.

Hot-air Drying Kinetics of Yam Slices under Step Change in Relative Humidity

2016 ◽  
Vol 12 (8) ◽  
pp. 783-792 ◽  
Author(s):  
Hao-Yu Ju ◽  
Qian Zhang ◽  
A.S. Mujumdar ◽  
Xiao-Ming Fang ◽  
Hong-Wei Xiao ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Weibull Model ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Rehydration Ratio ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air

Abstract The drying kinetics and mathematical modeling of hot-air drying of yam slices were investigated under two-stage relative humidity (RH) control strategy with 60 °C and 1.5 m/s as its constant drying temperature and air velocity, respectively. Results indicate high RH in the initial stage results in high sample’s temperature that enhances water diffusion in the falling rate drying period. Within the scope of current work, change in RH in the later drying period has insignificant influence on sample’s temperature rise while low RH can accelerate the drying rate. Compared to drying at constant 20 % RH at the same drying air temperature, the drying strategy of using 40 % RH over the first 15 min and then lowing to 20 % RH for the remainder time yields a shorter drying time. Weibull model adequately described the moisture content variation with time for all experiments with the scale parameter ranging from 105.02 to 122.38 min and the values of shape parameters from 0.988 to 1.183. The effective moisture diffusivity determined from the Weibull model varied from 2.032 to 2.610×10−8 m2/s. The rehydration ratio increased as the overall drying time was reduced. Microstructure examination shows that higher RH in the initial drying stage can lead to a more porous microstructure which enhances drying, while fast drying rate in the initial drying period generates a crust layer which hinders drying.

scholarly journals Intermittent–microwave and convective drying of parsley

2018 ◽  
Author(s):  
Justyna Szadzińska ◽  
Dominik Mierzwa
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Vitamin C ◽  
Product Quality ◽  
Color Change ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Rate ◽  
Drying Time ◽  
Microwave Application

The studies present convective drying of parsley with an intermittent microwave application. Eight different drying programs including convective drying (CV) were carried out in a laboratory-scale hybrid dryer. The influence of intermittent conditions on drying time, drying rate, energy efficiency and product quality was analysed. The results demonstrated that intermittent–microwave convective drying improves the drying kinetics and reduces energy consumption. Moreover, a higher retention of vitamin C, smaller color change and a better ability to rehydration were observed for the parsley samples dried using intermittent drying than for CV.Keywords: intermittent drying, microwaves, energy, vitamin C, rehydration.  

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

The Potential Migrated Mechanism of Water-Soluble Components in Pellets Prepared by Wet Extrusion/Spheronization: Effect of Drying Rate

2020 ◽  
Vol 17 ◽  
Author(s):  
Bingwei Wang ◽  
Jianping Liu ◽  
Zhenghua Li ◽  
Yulong Xia ◽  
Shuangshuang Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Drying Rate ◽  
Scanning Calorimetry ◽  
Drying Temperature ◽  
Wet Extrusion ◽  
Extrusion Spheronization ◽  
Soluble Components

Background: At present, there were numerous researches on the migration of components in tablets and granules, the investigation in the pharmaceutical literatrue concerning the effect of drying rate on the migration of water-soluble components of pellets was limited. Temperature and relative humidity (RH) were crucial parameters during the drying process which was an essential step in the preparation of pellets via wet extrusion/spheronization. To quantify these variables, the water loss percentage of pellets per minute was defined as drying rate. Objective: The study aimed to investigate the influence of drying rate on the migration of water-soluble components in wet pellets and the potential migrated mechanism. Methods: The pellets containing tartrazine as a water-soluble model drug and microcrystalline cellulose as a matrix former were prepared by extrusion/spheronization and dried at four different drying temperature and relative humidity. Afterward, the extent of migrated tartrazine was assessed regarding appearance, in-vitro dissolution test, Differential Scanning Calorimetry, X-Ray Powder Diffraction, Attenuated total reflectance Fourier transform infrared spectroscopy and Confocal Raman Mapping. Results: Results demonstrated that red spots of tartrazine appeared on the surface of pellets and more than 40% tartrazine were burst released within 5 minutes when pellets dried at 60℃/RH 10%. While pellets dried at 40℃/RH 80%, none of these aforementioned phenomena was observed. Conclusion: In conclusion, the faster drying rate was, the more tartrazine migrated to the exterior of pellets. Adjusting drying temperature and relative humidity appropriately could inhibit the migration of water-soluble components within wet extrusion/spheronization pellets.

scholarly journals Impact of Preharvest and Postharvest on Color Changes during Convective Drying of Mangoes

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 490
Author(s):  
Alioune Diop ◽  
Jean–Michel Méot ◽  
Mathieu Léchaudel ◽  
Frédéric Chiroleu ◽  
Nafissatou Diop Ndiaye ◽  
...  
Keyword(s):  
Regression Models ◽  
Convective Drying ◽  
Color Changes ◽  
Ripening Time ◽  
Physico Chemical ◽  
C 30 ◽  
The Impact

The purpose of this study was to evaluate the impact of the harvest stage, ripening conditions and maturity on color changes of cv. ‘Cogshall’ and cv. ‘Kent’ variety mangoes during drying. A total of four harvests were undertaken, and the fruits were ripened at 20 and 35 °C for five different ripening times at each temperature. At each ripening time, mangoes were dried at 60 °C/30% RH/1.5 m/s for 5 h. A wide physico-chemical and color variability of fresh and dry pulp was created. The relationships according to the L*, H* and C* coordinates were established using mixed covariance regression models in relation to the above pre- and postharvest (preprocess) parameters. According to the L* coordinate results, browning during drying was not affected by the preprocess parameters. However, dried slices from mangoes ripened at 35 °C exhibited better retention of the initial chroma, and had a greater decrease in hue than dried slices from mangoes ripened at 20 °C. However, fresh mango color, successfully managed by the pre- and postharvest conditions, had more impact on dried mango color than the studied parameters. The preprocess parameters were effective levers for improving fresh mango color, and consequently dried mango color.

scholarly journals Impact of temperature and relative humidity on the transmission of COVID-19: a modelling study in China and the United States

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043863
Author(s):  
Jingyuan Wang ◽  
Ke Tang ◽  
Kai Feng ◽  
Xin Lin ◽  
Weifeng Lv ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Relative Humidity ◽  
Human Mobility ◽  
The United States ◽  
Reproductive Number ◽  
Cross Sectional ◽  
The Usa ◽  
Higher Temperature ◽  
Potential Impact ◽  
The Impact

ObjectivesWe aim to assess the impact of temperature and relative humidity on the transmission of COVID-19 across communities after accounting for community-level factors such as demographics, socioeconomic status and human mobility status.DesignA retrospective cross-sectional regression analysis via the Fama-MacBeth procedure is adopted.SettingWe use the data for COVID-19 daily symptom-onset cases for 100 Chinese cities and COVID-19 daily confirmed cases for 1005 US counties.ParticipantsA total of 69 498 cases in China and 740 843 cases in the USA are used for calculating the effective reproductive numbers.Primary outcome measuresRegression analysis of the impact of temperature and relative humidity on the effective reproductive number (R value).ResultsStatistically significant negative correlations are found between temperature/relative humidity and the effective reproductive number (R value) in both China and the USA.ConclusionsHigher temperature and higher relative humidity potentially suppress the transmission of COVID-19. Specifically, an increase in temperature by 1°C is associated with a reduction in the R value of COVID-19 by 0.026 (95% CI (−0.0395 to −0.0125)) in China and by 0.020 (95% CI (−0.0311 to −0.0096)) in the USA; an increase in relative humidity by 1% is associated with a reduction in the R value by 0.0076 (95% CI (−0.0108 to −0.0045)) in China and by 0.0080 (95% CI (−0.0150 to −0.0010)) in the USA. Therefore, the potential impact of temperature/relative humidity on the effective reproductive number alone is not strong enough to stop the pandemic.

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