A Method for Determination of Porosity Change from Shrinkage Curves of Deformable Materials

Madiouli, Jamel; Lecomte, Didier; nganya, thomas; Chavez, Sofia; Sghaier, Jalila; Sammouda, Habib

doi:10.1080/07373930701227185

Cited by 60 publications

(66 citation statements)

References 27 publications

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“…It is clear from Figure 3 that, as expected, the thickness reduction was approximately proportional to the moisture content decrease. Madiouli et al (2007) commented on the fact that the choice of the drying process is significant in terms of final product shrinkage. Krokida and Brazilian Journal of Chemical Engineering Vol.…”

Section: Resultsmentioning

confidence: 99%

Drying kinetics, structural characteristics and vitamin C retention of dedo-de-moça pepper (Capsicum baccatum) during convective and freeze drying

Véras

Béttega

Freire

et al. 2012

Braz. J. Chem. Eng.

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-The main objective of this study was to evaluate the effect of the drying process on the vitamin C levels and physical properties of dedo-de-moça pepper. The drying kinetics and the structural properties were determined as a function of moisture content. Convective drying was compared with freeze-drying in terms of product quality, structural properties, retention of vitamin C and rehydration characteristics. Empirical and semi-empirical equations were used to describe the drying and rehydration kinetics. Nonlinear analysis applied to results of convective drying, based on curvature measures and bias measures, showed that the only equation that gives good inference results based on least squares estimators is the Overhults equation. The characterization of the rehydration process was done by determining the indexes that take into account the water absorption capacity and solutes losses. The material dried by lyophilization show greater potential to rehydrate.

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Section: Resultsmentioning

confidence: 99%

Drying kinetics, structural characteristics and vitamin C retention of dedo-de-moça pepper (Capsicum baccatum) during convective and freeze drying

Véras

Béttega

Freire

et al. 2012

Braz. J. Chem. Eng.

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“…The second approach is more fundamental and based on mass and volume balance equations, applicable to the wide range of products and drying conditions. It was developed by Vacarezza (1975), Perez and Calvelo (1984), Zogzas et al (1994), Wang and Brennan (1995), Rahman et al (1996), Mayor and Sereno (2004), Katekawa and Silva (2004), and Madiouli et al (2007). Vacarezza (1975) proposed the model of linear relationship between shrinkage and moisture (ideal shrinkage), appropriate for convective drying of fruits and vegetables.…”

Section: Introductionmentioning

confidence: 99%

“…However, they did not reveal fundamental relationship between moisture, shrinkage, density, and porosity based on geometrical considerations. The next contribution was made by Madiouli et al (2007) who proposed graphoanalytical method of porosity change determination from shrinkage curves of deformable materials. They analyzed all available expressions for shrinkage and concluded that bulk shrinkage (V/V 0 ) is the best indicator of the moisture loss (X/X 0 ) during the process of drying.…”

Section: Introductionmentioning

confidence: 99%

Porosity Evaluation of Ginseng Roots from Real-Time Imaging and Mass Measurements

Martynenko

2008

Food Bioprocess Technol

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Real-time imaging and mass measurements were used for evaluation of instantaneous porosity in convective drying of ginseng roots. Porosity changes were evaluated from moisture-shrinkage-porosity correlation. It was found that any deviation of shrinkage-moisture relationship from linearity was due to the changes of porosity. The impact of temperature on porosity development was evaluated from drying experiments at moderate (38°C) and high (50°C) temperatures. Drying at 38°C resulted in gradual increasing of porosity to 20-25% with the next quick decreasing of porosity to 10-15% at the end of drying due to intensive shrinkage. In contrast, drying at 50°C resulted in constant porosity (0-5%) for most of the drying period, with the next increasing to 30% at the end of drying due to the case hardening. The method of porosity evaluation was verified with direct microscopic measurements at different stages of drying.

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“…The real density was determined in a helium pycnometer, model 1000 Ultrapycometer of the brand Quantachrome Instruments. The shrinkage of samples was expressed in terms of the shrinkage coefficient V/V 0 , defined by Madiouli et al (2007). Moisture was determined in a chamber at 105 ± 5 °C for 24 hours.…”

Section: Characterizationmentioning

confidence: 99%

“…The kinetics of microwave drying was compared with those obtained in a lyophilizer and in convective drying by Prakash et al (2004). Zogzas et al (1994) and Madiouli et al (2007) presented different models for the representation of porosity, density and shrinkage of carrots during drying in a convective dryer. Krokida and Maroulis (1997) also suggested equations to determine the same properties of some fruits and vegetables, including carrots, during drying in several dryers, among them microwave dryers and lyophilizers.…”

Section: Introductionmentioning

confidence: 99%

Comparison of carrot (Daucus carota) drying in microwave and in vacuum microwave

Béttega

Rosa

Corrêa

et al. 2014

Braz. J. Chem. Eng.

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-Drying is a single operation employed to prolong the life of a large quantity of vegetables. Carrot (Daucus carota) drying has been the subject of many studies. This plant has been highlighted in the human diet for having high nutritional value, mainly due to the high content of β-carotene. In this work, carrot drying behavior was studied in a regular microwave dryer and a vacuum microwave dryer. A vacuum of 450 mmHg was applied for drying of carrot in different geometrical shapes (cubes, discs and sticks). The samples were dried at power ratings of 1.0 W/g, 1.5 W/g and 2.0 W/g for both methods of drying. The evolution of physical properties such as density, volume and porosity was monitored and related to the moisture content of the sample and to the method of drying and power rating used. The geometric shape of the sample influenced the drying kinetics and it was verified that the cubic form was responsible for a slower drying. The application of vacuum showed no major changes in the drying kinetics in microwave but influenced the physical properties of the material. The influence of power ratings on the content of β-carotene was also evaluated and discussed. The main difference observed was the lower shrinkage of the samples dried in the vacuum microwave compared to those dried only in microwave.

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A Method for Determination of Porosity Change from Shrinkage Curves of Deformable Materials

Cited by 60 publications

References 27 publications

Drying kinetics, structural characteristics and vitamin C retention of dedo-de-moça pepper (Capsicum baccatum) during convective and freeze drying

Drying kinetics, structural characteristics and vitamin C retention of dedo-de-moça pepper (Capsicum baccatum) during convective and freeze drying

Porosity Evaluation of Ginseng Roots from Real-Time Imaging and Mass Measurements

Comparison of carrot (Daucus carota) drying in microwave and in vacuum microwave

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