Moisture sorption isotherms of fresh and blanched pumpkin (Cucurbita moschata)

Filho, Lucídio Molina; Gonçalves, Ana Katherine; Mauro, Maria Aparecida; Frascareli, Elen Cristina

doi:10.1590/s0101-20612011000300025

Cited by 18 publications

(8 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was associated with tissue damage caused by blanching, as well as with the loss of sugars during this treatment, from the samples to the boiling water (Table 2) and consequent decrease in the equilibrium moisture, as low molecular mass carbohydrates such as sucrose and reducing sugars have higher capacity to retain water than cellulosic compounds and proteins, which, together with the sugars, are the major pumpkin components (Molina Filho et al 2011).…”

Section: Falling Drying Rate Periodmentioning

confidence: 99%

“…To evaluate the external resistance through the Biot mass number, κ was estimated using a water concentration range from the sorption curves determined for pumpkins (Molina Filho et al 2011). This permitted an evaluation of the Biot number magnitude from a correlation for flat plate that considers low mass transfer rates (Treybal 1980).…”

Section: Falling Drying Rate Periodmentioning

confidence: 99%

See 1 more Smart Citation

Effect of an Edible Pectin Coating and Blanching Pretreatments on the Air-Drying Kinetics of Pumpkin (Cucurbita moschata)

Filho

Frascareli

Mauro

2016

Food Bioprocess Technol

Self Cite

View full text Add to dashboard Cite

With the aim of making food drying processing data and their evaluation available, this work entails evaluating the air-drying kinetics of fresh pumpkin slices and those pre-treated by applying an edible pectin coating or blanching. The drying kinetics of the fresh, blanched, and pectin-coated pumpkin slices were evaluated at 60 and 70°C with air velocities of 0.85 and 1.70 m s −1 . The effects of the pre-treatments and drying parameters on moisture diffusivity were investigated. Under the drying conditions studied, a constant-rate period was found and the falling-rate period was described by the diffusion equation. In order to take shrinkage into account, shrinkage coefficients were incorporated in an approximate way, using the analytical solution of Fick's equation. The highest constant drying rate values were obtained for the blanched samples, followed by the coated samples and finally the fresh samples. Constant drying rates demonstrated that this period did not significantly influence the estimate of the effective diffusion coefficients. It was shown that the water diffusivity of the coating was high, but only slightly increased the drying time, thus not affecting drying efficiency. Conversely, blanching promoted more water transfer and enhanced drying efficiency. It was concluded that coating and blanching at the temperatures and velocities studied were promising for use as pre-treatments in the drying of pumpkins. Keywords Drying rate . Diffusivity . Shrinkage . Fick's equation Nomenclature A Surface area (m 2 ) α Fitting constant (dimensionless) D eff Effective diffusion coefficients of water (m 2 ⋅s −1 ) Bi M Mass transfer Biot number (dimensionless) e Thickness (m) kDrying rate constant (s −1 ) (Eq. 10 and 12) and (s −n ) (Eq. 11) k G Mass transfer coefficient (kg water⋅m −2 ⋅s −1 ⋅Pa −1 ) m s Dry sample mass (kg) n Number of terms of the series (Eq. 6); fitting constant (dimensionless) (Eq. 11); and number of observations (Eq. 13); N c Constant flow of evaporated water (kg water⋅m −2 ⋅s −1 ) P Mean percent error (%)Air velocity (m⋅s −1 ) w 0 Water content, w.b. (kg water⋅kg −1 wet matter) X Fractional or residual moisture, dry basis (dimensionless) X Water content, d.b. (kg water⋅kg −1 dry solids) X c Critical water content (kg water⋅kg −1 dry solids) X t ð Þ Mean fraction of the water mass, d.b. (kg water⋅kg −1 dry solids) y Experimental or calculated value γ n Roots of the transcendent equation tg(γ) = 1/γBi M

show abstract

Section: Falling Drying Rate Periodmentioning

confidence: 99%

Section: Falling Drying Rate Periodmentioning

confidence: 99%

Effect of an Edible Pectin Coating and Blanching Pretreatments on the Air-Drying Kinetics of Pumpkin (Cucurbita moschata)

Filho

Frascareli

Mauro

2016

Food Bioprocess Technol

Self Cite

View full text Add to dashboard Cite

show abstract

“…The moisture content was determined after reaching equilibrium. The experimental data of the isotherms were fitted to the GAB and BET mathematical models (MoLINA-FILho et al 2011), represented by the following equations:…”

Section: Sorption Isothermsmentioning

confidence: 99%

“…The efficiency of the fit was evaluated based on the determination coefficient (R 2 ) and on the relative mean module, P, as defined by eq. 3 (MoLINA-FILho et al, 2011). (3)…”

Section: Sorption Isothermsmentioning

confidence: 99%

Physical and morphological characteristics of edible coatings based on pectin and guava by-products applied to guava pieces

et al. 2022

Self Cite

View full text Add to dashboard Cite

Edible coatings based on polysaccharides have been applied on pieces of fruits and vegetables before drying because of their potential to improve physical and nutritional characteristics of dehydrated plant foods. In the present study, physical and thermal properties of pectin-based films, with and without the incorporation of by-products obtained from the processing of red guava, were determined. These properties allow one to predict the likely behaviour of these films when used as edible coatings on guava pieces, during and after their dehydration. Thus the structural and morphological characteristics and the physical, thermal and sorption properties of the films and of the fruit pulp were determined, using scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and the static gravimetric method to determine the water-sorption curves. The addition of by-products provided crystallinity to the pectin film, attributed to their cellulose content, and hardly altered the water retention capacity of the pectin films. However, the pectin contributed to presenting a slightly higher sorption moisture at equilibrium, as compared to the guava pulp. The glass transition temperatures reported at extremely low moisture contents, both in the pulp and in the films with added by-products, indicated that at intermediate moisture contents, the fruit/film ensemble was in the rubbery state at room temperatures, providing softness to the dehydrated product. The images showed good integration of the edible films with the surface of the guava pieces.

show abstract

“…Sorption Isotherms. Sorption isotherms of the films (2 × 2 cm) were determined based on the static gravimetric methods described by Filho et al 38 Eight saturated aqueous salt solutions corresponding to water activity intervals between 0.11 and 0.90 (salt-%UR: LiCl-0.11; CH 3 COOK-0.23; MgCl 2 -0.33; K 2 CO 3 -0.43; NaBr-0.58; NaNO 2 -0.66; NaCl-0.75; KCl-0.84; and BaCl 2 -0.90) were prepared. The Guggenheim-Anderson-de Boer (GAB) mathematical model was adjusted to the experimental data using nonlinear regression.…”

Section: Characterization Of Spi + Pec Filmsmentioning

confidence: 99%

Effects of interactions between soy protein isolate and pectin on properties of soy protein‐based films

Amado

Silva

Mauro

2019

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

Composite films in coacervation condition offer an alternative to change properties of protein‐based films, and they present potential applications such as inclusion, stabilization, and release of bioactive compounds in foods. Maximum interactions between soy protein isolate (SPI) (5%) and high methoxyl pectin (PEC) (0.5, 1, 1.5, and 2%), by zeta potential analysis, are found at a pH of 3. The transparency of the SPI films is lost at this pH. When PEC is added to SPI films, the elasticity, solubility, and permeability to water vapor are not significantly altered, but the tensile strength increases. Permeabilities to oxygen are higher for low PEC contents, but as PEC is added, their values are typical of SPI films produced at a pH of 11. A homogeneous structure is found at the higher PEC concentrations. The interactions of PEC–SPI can be useful to tailor films and coatings for applications such as to carry and protect substances of interest. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48732.

show abstract

Moisture sorption isotherms of fresh and blanched pumpkin (Cucurbita moschata)

Cited by 18 publications

References 27 publications

Effect of an Edible Pectin Coating and Blanching Pretreatments on the Air-Drying Kinetics of Pumpkin (Cucurbita moschata)

Effect of an Edible Pectin Coating and Blanching Pretreatments on the Air-Drying Kinetics of Pumpkin (Cucurbita moschata)

Physical and morphological characteristics of edible coatings based on pectin and guava by-products applied to guava pieces

Effects of interactions between soy protein isolate and pectin on properties of soy protein‐based films

Contact Info

Product

Resources

About