Penetration rates into heterogeneous model systems and soluble food material

Penetration rates into heterogeneous model systems and soluble food material

Wetting as the first step during food powder reconstitution strongly depends on the interactions of wetting liquid and particle surface, expressed by the contact angle. Due to the heterogeneous composition of food materials including hydrophilic and hydrophobic surfaces, also the wetting process is...

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Bibliographic Details
Published in:Powder technology Vol. 339; pp. 765 - 774
Main Authors: Kammerhofer, J., Fries, L., Dymala, T., Dupas, J., Forny, L., Heinrich, S., Palzer, S.
Format: Journal Article
Language:English
Published: Lausanne Elsevier B.V 01-11-2018
Elsevier BV
Subjects:
Capillary rise
Contact angle
Data processing
Differential equations
Dissolution
Food
Food composition
Food powder
Heterogeneous system
Hydrophilic surfaces
Hydrophobic surfaces
Hydrophobicity
Kinetics
Mass transfer
Mathematical models
Modelling
Penetration
Penetration rate
Porosity
Powder
Powder beds
Solubility
Sucrose
Sugar
Viscosity
Wettability
Wetting
Penetration rate
Heterogeneous system
Modelling
Capillary rise
Dissolution
Food powder
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Summary:Wetting as the first step during food powder reconstitution strongly depends on the interactions of wetting liquid and particle surface, expressed by the contact angle. Due to the heterogeneous composition of food materials including hydrophilic and hydrophobic surfaces, also the wetting process is of heterogeneous nature. Furthermore, the solubility of food ingredients, such as sugars, increases the complexity of understanding and describing the wettability. In this study, we compared experimental water penetration into inert model powders containing hydrophilic and hydrophobic surfaces with theoretical penetration rates which were calculated by modifying a Washburn-based approach for the application to heterogeneous systems. A fair agreement was found when adjusting the porosity of the powder bed. In a second step, the inert powder was replaced by sucrose to introduce the effect of solubility. Since in presence of sucrose the model for inert systems can no longer describe experimentally observed penetration rates, we developed a model for water penetration into food powders considering solute concentration dependent liquid properties. The model is based on the solution of a coupled system of two differential equations representing capillary rise into a pore network and the mass transfer equation. Viscosity was found to have a major influence on the wetting kinetics. Our model predicts penetration rates during the first few seconds which are close to the experimental data. This allows us to conclude that it is suitable for predicting the first seconds of capillary penetration into a particulate system consisting of soluble sucrose. [Display omitted] •Critical hydrophobic concentration changes wetting rate•Pore blockage due to hydrophobic walls reduces effective porosity•Agreement of theoretical and experimental penetration rates in heterogeneous system•Development of model predicting penetration in soluble sucrose powder•Evaluation of predicted penetration rates into sucrose powder with experiments
ISSN:0032-5910
1873-328X
DOI:10.1016/j.powtec.2018.08.068