DRYING KINETICS OF WEST INDIAN CHERRY: INFLUENCE OF OSMOTIC PRETREATMENT

The purpose of this work was to study the influence of osmotic pretreatment on the convective drying kinetics of the West Indian cherry (Malpighia emarginata DC). Osmotic dehydration was performed with a 65ºBrix sucrose solution at room temperature, having the fruits immersed for 4 or 12 hours, using a 1:10 proportion of fruit:solution (w:w). After the osmotic dehydration, the fruits were convectively-dried at 50ºC on a tray dryer. The convection drying was modeled based on Fick’s second law, while the effective mass diffusion (Def) was determined using Levenberg-Marquardt’s minimization algorithm by means of the paradigm of inverse methods. The values of effective mass diffusion coefficients observed were in the same order of magnitude as those reported in the literature. The condition that promoted the highest value of diffusivity was convective drying preceded by 4 hours of osmotic dehydration. This condition was also the one with the best fit agreement of the tested model.

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Influence of Osmotic Pre-treatment on Convective Drying Kinetics of Figs

International Journal of Food Engineering ◽

10.1515/ijfe-2012-0020 ◽

2013 ◽

Vol 9 (2) ◽

pp. 187-196 ◽

Cited By ~ 8

Author(s):

Juliana M. Silva ◽

Muriel G. Cantu ◽

Vera Rodrigues ◽

Marcio A. Mazutti

Keyword(s):

Experimental Data ◽

Moisture Content ◽

Osmotic Dehydration ◽

Sucrose Concentration ◽

Drying Kinetics ◽

Soluble Solids ◽

Convective Drying ◽

Final Time ◽

Osmotic Treatment ◽

Kinetics Of

AbstractThis work evaluated the effects of osmotic dehydration on convective drying kinetics of figs. It used the experimental design methodology to evaluate the influence of sucrose concentration, temperature and time on the amount of total soluble solids (TSS) and moisture content of the figs. After the osmotic dehydration, it evaluated the convective drying kinetics at temperatures from 55 to 75°C. A mathematical model was employed to fit the experimental data. From the experimental data of the osmotic dehydration, it was seen that the moisture content of the figs after the treatment was closely related to the amount of TSS of the figs. Low moisture content and high TSS content were obtained for a narrow range of independent variables comprised between 55–60°C, 55–63 wt% and 260–280 min for temperature, sucrose concentration and exposure time, respectively. In the convective drying kinetics of the figs, there were no verified significant differences in the final time of drying of non-treated and osmotically dehydrated figs. However, the shrinkage was considerably reduced in the osmotically treated figs. The use of osmotic treatment enables the obtainment of figs softer than the simple use of convective drying without changing the final time of drying.

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Convective drying kinetics of osmotically pretreated papaya cubes

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v24n3p200-208 ◽

2020 ◽

Vol 24 (3) ◽

pp. 200-208 ◽

Cited By ~ 2

Author(s):

João P. de L. Ferreira ◽

Deise S. de Castro ◽

Inacia dos S. Moreira ◽

Wilton P. da Silva ◽

Rossana M. F. de Figueirêdo ◽

...

Keyword(s):

Mathematical Models ◽

Air Temperature ◽

Removal Rate ◽

Osmotic Dehydration ◽

Effective Diffusion ◽

Drying Kinetics ◽

Convective Drying ◽

Transfer Coefficients ◽

Thin Layer Drying ◽

Kinetics Of

ABSTRACT This study assessed the fitting of mathematical models to the convective drying kinetics of osmotically pre-dehydrated papaya cubes. Papaya cubes were subjected to osmotic dehydration in sucrose solutions at 40 and 50 ºBrix, at temperatures of 50 and 60 ºC, followed by complementary convective drying in forced air circulation oven under three temperatures (50, 60 and 70 °C) and constant air velocity of 1.0 m s-1. Ten thin-layer drying mathematical models were fitted to the experimental data. The increase in air temperature and the decrease in osmotic solution concentration resulted in increased water removal rate. Based on the statistical indices, the Two Terms model was the one that best described the drying kinetics of the samples for all evaluated conditions. The effective diffusion coefficients increased with the elevation of air temperature, ranging from 1.766 x 10-10 to 3.910 x 10-6 m2 s-1, whereas the convective mass transfer coefficients ranged from 3.910 x 10-7 to 1.201 x 10-6 m s-1 with Biot number from 0.001 to 12.500.

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Mathematical modeling of pequi pulp drying and effective diffusivity determination

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v21n7p493-498 ◽

2017 ◽

Vol 21 (7) ◽

pp. 493-498 ◽

Cited By ~ 3

Author(s):

Elisabete P. de Sousa ◽

Rossana M. F. de Figueirêdo ◽

Josivanda P. Gomes ◽

Alexandre J. de M. Queiroz ◽

Deise S. de Castro ◽

...

Keyword(s):

Experimental Data ◽

Effective Diffusivity ◽

Drying Kinetics ◽

Convective Drying ◽

Drying Time ◽

Air Speed ◽

Drying Curves ◽

Increasing Temperature ◽

Kinetics Of ◽

Best Fit

ABSTRACT The aim of this work was to study the drying kinetics of pequi pulp by convective drying at different conditions of temperature (50, 60, 70 and 80 °C) and thickness (0.5, 1.0 and 1.5 cm) at the air speed of 1.0 m s-1, with no addition of adjuvant. The experimental data of pequi pulp drying kinetics were used to plot drying curves and fitted to the models: Midilli, Page, Henderson & Pabis and Newton. Effective diffusivity was calculated using the Fick’s diffusion model for a flat plate. It was found that, with increasing thickness, the drying time increased and, with increasing temperature, the drying time was reduced. The Midilli model showed the best fit to the experimental data of pequi pulp drying at all temperatures and thicknesses, presenting higher coefficients of determination (R2), indicating that this model satisfactorily represents the pequi pulp drying phenomenon. There was a trend of increase in the effective diffusivity with the increase in pulp layer thickness and temperature.

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