Evaluation of a concentrated parameters mathematical model applied to drying of yerba mate leaves with variable mass transfer coefficient

Pilatti, Daniel; Johann, Gracielle; Palú, Fernando; Silva, Edson Antônio da

doi:10.1016/j.applthermaleng.2016.02.139

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…The relationship between effective moisture diffusivity and drying temperatures was described by an Arrhenius-type equation (Equation (7)) [ 41 , 42 , 43 ].

where D 0 is the pre-exponential factor (m 2 s −1 ), E a is the activation energy (J mol −1 ), R is the universal gas constant (8.314 J mol −1 K −1 ), and T is the temperature (°C).…”

Section: Methodsmentioning

confidence: 99%

Mathematical Models to Describe the Foam Mat Drying Process of Cumbeba Pulp (Tacinga inamoena) and Product Quality

Diógenes

Figueirêdo

Queiroz

et al. 2022

Foods

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The present study investigated the mathematical modeling foam-mat drying kinetics of cumbeba pulp and the effect of drying conditions on the color and contents of ascorbic acid, flavonoids, and phenolic compounds of the powder pulps obtained. Foam-mat drying was carried out in a forced air circulation oven at temperatures of 50, 60, and 70 °C, testing foam-mat thicknesses of 0.5, 1.0, and 1.5 cm. The increase in the water removal rate is a result of the increase in air temperature and the decrease in the thickness of the foam layer. Among the empirical and semi-empirical mathematical models, the Midilli model was the one that best represented the drying curves in all conditions evaluated. Effective water diffusivity ranged from 1.037 × 10−9 to 6.103 × 10−9 m2 s−1, with activation energy of 25.212, 33.397, and 36.609 kJ mol−1 for foam thicknesses of 0.5, 1.0, and 1.5 cm, respectively. Cumbeba powders showed light orangish colors and, as the drying temperature increased from 50 to 70 °C, for all thicknesses, the lightness value (L*) decreased and the values of redness (+a*) and yellowness (+b*) increased. Foam-mat drying at higher temperatures (60 and 70 °C) improved the retention of ascorbic acid and flavonoids, but reduced the content of phenolic compounds, while the increase in thickness, especially for flavonoids and phenolic compounds, caused reduction in their contents. The foam-mat drying method allowed obtaining a good-quality cumbeba pulp powder.

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“…The relationship between effective moisture diffusivity and drying temperatures was described by an Arrhenius-type equation (Equation (7)) [ 41 , 42 , 43 ].

where D 0 is the pre-exponential factor (m 2 s −1 ), E a is the activation energy (J mol −1 ), R is the universal gas constant (8.314 J mol −1 K −1 ), and T is the temperature (°C).…”

Section: Methodsmentioning

confidence: 99%

Mathematical Models to Describe the Foam Mat Drying Process of Cumbeba Pulp (Tacinga inamoena) and Product Quality

Diógenes

Figueirêdo

Queiroz

et al. 2022

Foods

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show abstract

“…In the present study, an Arrhenius-type equation, Equation (10), was used to relate the effective mass diffusivity (D eff ) and drying air temperature (T) [ 25 , 91 , 92 ]:

where D o is the pre-exponential factor (m 2 /s), E a is the activation energy (kJ/mol), R is the universal constant of gases (0.008314 kJ/mol K) and T is the drying air temperature (°C).…”

Section: Methodsmentioning

confidence: 99%

Utilization of Cumbeba (Tacinga inamoena) Residue: Drying Kinetics and Effect of Process Conditions on Antioxidant Bioactive Compounds

Ferreira

Queiroz

Figueirêdo

et al. 2021

Foods

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The residue generated from the processing of Tacinga inamoena (cumbeba) fruit pulp represents a large amount of material that is discarded without proper application. Despite that, it is a raw material that is source of ascorbic acid, carotenoids and phenolic compounds, which are valued in nutraceutical diets for allegedly combating free radicals generated in metabolism. This research paper presents a study focused on the mathematical modeling of drying kinetics and the effect of the process on the level of bioactive of cumbeba residue. The experiments of cumbeba residue drying (untreated or whole residue (WR), crushed residue (CR) and residue in the form of foam (FR)) were carried out in a fixed-bed dryer at four air temperatures (50, 60, 70 and 80 °C). Effective water diffusivity (Deff) was determined by the inverse method and its dependence on temperature was described by an Arrhenius-type equation. It was observed that, regardless of the type of pretreatment, the increase in air temperature resulted in higher rate of water removal. The Midilli model showed better simulation of cumbeba residue drying kinetics than the other models tested within the experimental temperature range studied. Effective water diffusivity (Deff) ranged from 6.4890 to 11.1900 × 10−6 m2/s, 2.9285 to 12.754 × 10−9 m2/s and 1.5393 × 10−8 to 12.4270 × 10−6 m2/s with activation energy of 22.3078, 46.7115 and 58.0736 kJ/mol within the temperature range of 50–80 °C obtained for the whole cumbeba, crushed cumbeba and cumbeba residue in the form of foam, respectively. In relation to bioactive compounds, it was observed that for a fixed temperature the whole residue had higher retention of bioactive compounds, especially phenolic compounds, whereas the crushed residue and the residue in the form of foam had intermediate and lower levels, respectively. This study provides evidence that cumbeba residue in its whole form can be used for the recovery of natural antioxidant bioactive compounds, mainly phenolic compounds, with the possibility of application in the food and pharmaceutical industries.

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“…The Arrhenius equation (Equation 7) (Pilatti et al, 2016;Tzempelikos et al, 2015) was used to describe the relationship between the effective moisture diffusivity and the drying temperatures of "biribá" pulp foam.…”

Section: Computation Of Activation Energymentioning

confidence: 99%

Effects of foam‐mat drying temperature on thermodynamic properties, microstructural properties, and X‐ray diffraction of Biribá (Rollinia mucosa [Jacq.] Baill) pulp

Souza

Aquino

Santos

et al. 2022

J Food Process Engineering

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This study aimed to dry the pulp of "Biribá" (Rollinia mucosa [Jacq.] Baill) using the foam-mat drying method at the temperatures of 30 C, 40 C, 50 C, and 60 C, fit different mathematical models to the experimental data, calculate the thermodynamic properties, and analyze the powders produced for water activity, morphology, and Xray diffraction. The results showed that the Midilli model, for having the highest coefficients of determination and low values of mean squared deviation and chi-square, could be selected as the most suitable to predict the drying kinetics of "biribá." The effective diffusivity was on the order of 10 À10 m 2 s À1 , and the Arrhenius equation evidenced dependence of this parameter with drying air temperature, which showed an activation energy of 53.47 kJ mol À1 . The thermodynamic properties indicated the existence of an endergonic process. "Biribá" powders showed water activity ranging from .44 to .54 and porous, irregular, and agglomerated morphological structures, with X-ray diffractograms characteristic of amorphous materials. Practical applicationsIn this study, foam-mat drying characteristics of "Biribá" (Rollinia mucosa [Jacq.] Baill) pulp were investigated in a food dehydrator. The effect of different temperatures on drying characteristics and thermodynamic properties, and water activity, microstructural properties and X-ray diffraction of the powders produced was determined. This information may help to optimize the process conditions and reduce costs of processing and packaging.

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Evaluation of a concentrated parameters mathematical model applied to drying of yerba mate leaves with variable mass transfer coefficient

Cited by 15 publications

References 27 publications

Mathematical Models to Describe the Foam Mat Drying Process of Cumbeba Pulp (Tacinga inamoena) and Product Quality

Mathematical Models to Describe the Foam Mat Drying Process of Cumbeba Pulp (Tacinga inamoena) and Product Quality

Utilization of Cumbeba (Tacinga inamoena) Residue: Drying Kinetics and Effect of Process Conditions on Antioxidant Bioactive Compounds

Effects of foam‐mat drying temperature on thermodynamic properties, microstructural properties, and X‐ray diffraction of Biribá (Rollinia mucosa [Jacq.] Baill) pulp

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