Moisture diffusion by the fractional-time model in convective drying with ultrasound-ethanol pretreatment of banana slices

2022 ◽  
pp. 102933
Author(s):  
Suian José Granella ◽  
Taise Raquel Bechlin ◽  
Divair Christ
Keyword(s):  
Moisture Diffusion ◽  
Convective Drying ◽  
Time Model ◽  
Ethanol Pretreatment

scholarly journals Drying Kinetics and Modelling of Convective Drying of Kedondong Fruit

2021 ◽  
Vol 21 (1) ◽  
pp. 93
Author(s):  
Cheak Theng Ee ◽  
Yee Jian Khaw ◽  
Ching Lik Hii ◽  
Choon Lai Chiang ◽  
Mohamad Djaeni
Keyword(s):  
Thin Layer ◽  
Moisture Diffusion ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Small Scale ◽  
Hot Air ◽  
Kinetic Information ◽  
Drying Rates ◽  
Drying Curves ◽  
Effective Diffusivities

Kedondong is an underutilized fruit cultivated in a small scale in Malaysia and it contains nutrients that can be preserved through drying. The dried product can be sold as a premium fruit snack that could generate revenue for the producer. We studied the drying of peeled and unpeeled kedondong fruits using hot air (60-80°C). This study aims to investigate the drying kinetics (drying rates and effective diffusivities) of kedondong fruits and model the drying curves using thin layer models. Ten thin layer models were employed and solved using non-linear regression. Drying kinetics showed that only falling rate periods were observed, which implied that internal diffusion was the dominant mechanism for moisture release. Mathematical models showed that Modified Hii et al. (I) and (II) models were able to predict the drying curve well with the highest R2 (0.9992-0.9999), the lowest RMSE (8.0 x 10-4 - 2.5 x 10-3) and the lowest χ2 (4.0 ×10-5 - 2.0 x 10-4). Peeled  samples showed higher effective diffusivities (average 3.2 x 10-11 m2/s)  than unpeeled samples (average 2.7 x 10-11 m2/s). The activation energy was lower in peeled samples (25.8 kJ/mol) as moisture diffusion could occur more easily than unpeeled samples (32.1 kJ/mol). Results from this study provide kinetic information that can be used in scaling up of dryer and optimizing dryer performances.

scholarly journals Study of the drying kinetics and calculation of mass transfer properties in hot air drying of Cynara cardunculus

2020 ◽  
Vol 5 (1) ◽  
pp. 740-750
Author(s):  
Raquel P. F. Guiné ◽  
Maria João Lima
Keyword(s):  
Mass Transfer ◽  
Thin Layer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Moisture Diffusion ◽  
Equation Model ◽  
Convective Drying ◽  
Cynara Cardunculus ◽  
Thin Layer Drying ◽  
Transfer Properties

AbstractIn the present work, mass transfer properties of thistle flower (Cynara cardunculus L.) were evaluated for the convective drying carried out at temperatures between 35 and 65°C, with an air flow of 0.5 m/s. The calculations followed two different algorithms, based on mathematical models derived from the thin layer drying equation and Fick’s second law of diffusion. The results obtained indicated that different methodologies resulted in different values of mass transfer properties, which is an alert that care must be taken when choosing which calculation method might be more appropriate in a specific practical application. In all cases, the values of moisture diffusion and mass transfer coefficient were found to increase with increasing operating temperature. The values of diffusivity increased from 2.7866 × 10−9 to 1.4027 × 10−8 m2/s for the thin layer model-based algorithm and from 1.9256 × 10−10 to 1.2033 × 10−9 m2/s for Fick’s equation model. The values of the mass transfer coefficient increased from 8.4335 × 10−8 to 8.4400 × 10−7 m/s and from 5.8277 × 10−9 to 7.2398 × 10−8 m/s, respectively, for the thin layer and Fick’s law-based models.

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.

scholarly journals The intensification of dehydration process of pectin-containing raw materials

10.5219/1711 ◽  
2022 ◽  
Vol 16 ◽  
pp. 15-26
Author(s):  
Igor Palamarchuk ◽  
Oksana Zozulyak ◽  
Mikhailo Mushtruk ◽  
Ievgenii Petrychenko ◽  
Nataliia Slobodyanyuk ◽  
...  
Keyword(s):  
Raw Materials ◽  
Fixed Bed ◽  
Low Frequency ◽  
Moisture Diffusion ◽  
Convective Drying ◽  
Simultaneous Application ◽  
Low Frequency Oscillations ◽  
Mechanical Factors ◽  
Oscillating Motion ◽  
Kinetics Of

The process of intensifying dehydration of pectin-containing raw materials by using centrifugation with simultaneous application of low-frequency oscillations to the working container creates an electroosmotic effect in unilateral diffusion to improve the filtration process. It is established that to reduce the technological resistance in the presented methods; it is necessary to create a fluidized bed of products due to the oscillating motion of the working capacity. An experimental vibration unit has been developed to determine the rational parameters of the vibrocentric moisture removal process using the electroosmotic effect. It is proved that the complex of the designed equipment provides consecutive carrying out of three-stage vibration filtration-convective drying of high-moisture production by an alternation of action of a stream of the heat carrier, an electromagnetic field, low-frequency fluctuations. According to the research results, the dependences of the kinetics of the moisture diffusion process on the electric field strength are obtained; frequency of electric current and duty cycle of pulses, which allowed to optimize the process parameters according to the criteria of minimizing energy consumption. It was found that the processing time to achieve the desired humidity with the application of vibration, filtration, and electroosmotic effect was twice less than for filtration drying in a fixed bed. In combination with the noted physical and mechanical factors, the proposed technology improves the technical and economic parameters of the studied process.

scholarly journals Effect of ethanol pretreatment on melon convective drying

2020 ◽  
Vol 333 ◽  
pp. 127502 ◽  
Author(s):  
Renata Masur Carneiro da Cunha ◽  
Shirley Clyde Rupert Brandão ◽  
Rafael Augusto Batista de Medeiros ◽  
Edvaldo Vieira da Silva Júnior ◽  
João Henrique Fernandes da Silva ◽  
...  
Keyword(s):  
Convective Drying ◽  
Ethanol Pretreatment

Black soldier fly (Hermetia illucens, L.) larvae for food and feed: modelling drying kinetics

2021 ◽  
pp. 1-12
Author(s):  
M.N. Coelho Pinheiro ◽  
N. Ribeiro ◽  
P. da Silva ◽  
R. Costa
Keyword(s):  
Boundary Conditions ◽  
Water Content ◽  
Water Loss ◽  
Moisture Diffusion ◽  
Convective Drying ◽  
Transfer Model ◽  
Black Soldier Fly ◽  
Small Influence ◽  
Food And Feed ◽  
Black Soldier Fly Larvae

Insects are a new alternative for food and feed and a solution for circular economy. Among the most promising insects, black soldier fly, mainly in the larvae phase, is a solution specially for feed, and in particular in its dried form. The aim of this work was to study the water loss transfer during convective drying of black soldier fly larvae (BSFL). The mass transfer model consisted of mass diffusion with two alternative boundary conditions (no external resistance and convection) and with/without shrinkage, applied with finite elements method, with a triangular mesh of 3,036 elements and a geometry reproducing the shape of the larvae. The moisture diffusion coefficient, estimated from the experimental data assuming an infinite slab, increased from 0.7002×10-10 m2/s at 60 °C to 2.792×10-10 m2/s at 90 °C, with an activation energy of 43.97 kJ/mol. The simulation predicted with detail the water content profile showing a quick water loss on the outer layers of the BSFL at the initial times. The evolution of the overall water content of BSFL during drying was better predicted for long times (when more than 80% of the moisture was removed) and at the highest temperature of 90 °C and showed that diffusion was the dominating mechanism, with small influence of the boundary conditions studied. Although shrinkage between 21 and 29% was considered, depending on the temperature, the inclusion of volume change in the model did not significantly improved the water content prediction.

scholarly journals Drying kinetics and mass transfer properties in the drying of thistle flower

2019 ◽  
Vol 22 ◽  
Author(s):  
Raquel P. F. Guiné ◽  
Luísa Fontes ◽  
Maria João Reis Lima
Keyword(s):  
Mass Transfer ◽  
Effective Diffusivity ◽  
Moisture Diffusion ◽  
Convective Drying ◽  
Milk Clotting ◽  
Constant Rate ◽  
Different Temperatures ◽  
Drying Conditions ◽  
Transfer Properties ◽  
Natural Drying

Abstract Thistle flowers, and particularly their stigmas, are used to coagulate milk in the production of a number of traditional Portuguese cheeses due to their high milk-clotting activity provided by the high content of aspartic proteases. The aim of the present work was to determine the mass transfer properties of thistle flower under different drying conditions: natural drying and convective drying. Convective drying took place in a convection chamber set at different temperatures (35 to 65 °C) and the process was terminated when the sample presented a moisture content of about 5% or less. The traditional drying method was also used, placing the thistle flowers in a dry place sheltered from the sun, and leaving them to dehydrate at the variable room temperature. The present work allowed for the conclusion that convective drying was much faster than natural drying, and that the drying rate increased with temperature. The drying curve revealed an initial constant rate period followed by a falling rate. All the five thin layer models tested to fit the experimental data were shown to adequately describe the drying of the thistle flowers, but the best one was the Page model. The drying constant increased with temperature as did the effective diffusivity and the mass transfer coefficient. The results allowed one to estimate the activation energy for moisture diffusion (57 kJ/mol) and for convective mass transfer (78 kJ/mol). Thus this study showed the possibilities for designing efficient drying processes for the thistle flower used for milk-clotting in the manufacture of traditional cheeses.

Controlling mechanisms of moisture diffusion in convective drying of leather

2016 ◽  
Vol 53 (4) ◽  
pp. 1237-1245 ◽  
Author(s):  
Naima Benmakhlouf ◽  
Soufien Azzouz ◽  
Juan Monzó-Cabrera ◽  
Hechmi Khdhira ◽  
Afif ELCafsi
Keyword(s):  
Moisture Diffusion ◽  
Convective Drying

The Influence of Convective, Microwave Vacuum and Microwave-Assisted Drying on Blueberry Pomace Physicochemical Properties

2018 ◽  
Vol 14 (3) ◽  
Author(s):  
Magdalena Zielinska ◽  
Anna Michalska
Keyword(s):  
Antioxidant Capacity ◽  
Bioactive Compounds ◽  
Moisture Diffusion ◽  
Convective Drying ◽  
Drying Time ◽  
Microwave Vacuum Drying ◽  
Microwave Assisted ◽  
Hot Air ◽  
Tp 39 ◽  
Monomeric Anthocyanins

AbstractThe effect of hot air convective drying (HACD), microwave-vacuum drying (MWVD) and combined drying (HACD + MWVD) on the drying kinetics, bioactive compounds and color of blueberry pomace was evaluated. Drying time of blueberry pomace ranged from 0.6 to 6.7 h and moisture diffusion coefficients ranged from 7.94 × 10–8 to 1.83 × 10–7 m2/s. Drying caused degradation of total polyphenolics (TP) (39–76%), monomeric anthocyanins (21–77%) and antioxidant capacity values (24–76%). Drying time was shortened even by 91%, when MWVD was used instead of HACD. MWVD of blueberry pomace resulted in the smallest, while HACD at 60°C in the greatest loss of bioactive compounds and antioxidant capacity. HACD at 60°C + MWVD allowed to obtain a product with a higher content of TP, monomeric anthocyanins and a stronger antioxidant capacity than HACD at 90°C + MWVD. Combination of HACD at 60°C with MWVD allowed for the shortening of HACD time by 75% as well as for hapering the chemical changes as compared to HACD at 60°C. Even when the combination of HACD at 90°C with MWVD shortened the drying time by 68%, it did not improve the retention of TP, monomeric anthocyanins and antioxidant capacity when compared to HACD at 90°C.

scholarly journals Effect of Pretreatments on Convective and Infrared Drying Kinetics, Energy Consumption and Quality of Terebinth

2021 ◽  
Vol 11 (16) ◽  
pp. 7672
Author(s):  
Yousef Abbaspour-Gilandeh ◽  
Mohammad Kaveh ◽  
Hamideh Fatemi ◽  
Esmail Khalife ◽  
Dorota Witrowa-Rajchert ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Bioactive Compounds ◽  
Specific Energy Consumption ◽  
Moisture Diffusion ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Time And Energy

This study is focused on the influence of convective drying (50, 60, and 70 °C) and infrared (IR) power (250, 500, and 750 W) on the drying kinetics, the specific energy consumption of terebinth drying as well as quality and bioactive compounds upon various pretreatments such as ultrasound (US), blanching (BL), and microwave (MW). Compared to convective drying, IR drying decreased more the drying time and energy consumption (SEC). Application of higher IR powers and air temperatures accelerated the drying process at lower energy consumption (SEC) and higher energy efficiency and moisture diffusion. Terebinth dried by a convective dryer at 60 °C with US pretreatment showed a better color compared to other samples. It also exhibited the polyphenol and flavonoid content of 145.35 mg GAE/g d.m. and 49.24 mg QE/g d.m., respectively, with color variations of 14.25 and a rehydration rate of 3.17. The proposed pretreatment methods significantly reduced the drying time and energy consumption, and from the other side it increased energy efficiency, bioactive compounds, and quality of the dried samples (p < 0.01). Among the different pretreatments used, microwave pretreatment led to the best results in terms of the drying time and SEC, and energy efficiency. US pretreatment showed the best results in terms of preserving the bioactive compounds and the general appearance of the terebinth.

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