Pore development in viscoelastic foods during drying

Area of Science:

• Food science and engineering
• Materials science
• Drying technology

Background:

• Drying of food materials can lead to pore formation and cavitation.
• Viscoelastic properties and energy transport are crucial during food drying.
• Existing models do not fully capture the complex behavior of food materials during drying.

Purpose of the Study:

• To develop a numerical model for pore formation and cavitation in viscoelastic food materials during drying.
• To investigate the influence of material properties, such as viscoelasticity and a rigid skin, on pore inflation.
• To incorporate energy transport and temperature-dependent viscoelasticity into the model.

Main Methods:

• Idealized food material as a spherical object with a core/shell structure and a central gas-filled cavity.
• Modeled inhomogeneous large deformation of soft materials, coupling stress to moisture transport.
• Extended existing frameworks with energy transport and viscoelasticity, making relaxation times dependent on the glass transition temperature to product temperature ratio (Tg/T).

Main Results:

• The model describes pore formation/cavitation in viscoelastic food materials during drying.
• Demonstrated that pore inflation is contingent upon the food material's skin entering a glassy state.
• The findings align with observations during the spray drying of soft food materials.

Conclusions:

• The developed numerical model accurately predicts pore inflation and cavitation in viscoelastic food materials.
• The glassy state of the skin is a critical factor for pore inflation during drying.
• This research provides insights into controlling food structure during drying processes.