Microstructural characterization of a wheat-based food material using image analysis and pore network modeling during...

Area of Science:

• Food Science and Technology
• Materials Science
• Chemical Engineering

Background:

• Baking significantly impacts wheat-based food microstructure, influencing mechanical properties and consumer acceptance.
• Understanding these microstructural changes is crucial for optimizing baking processes and product quality.

Purpose of the Study:

• To analyze the microstructural variations in cookies during baking using advanced imaging and modeling techniques.
• To quantify key properties like porosity, pore size distribution, tortuosity, and permeability as a function of baking time.

Main Methods:

• Utilized X-ray micro-computed tomography to capture over 1500 2D images per sample.
• Applied image processing and pore network modeling to determine microstructural parameters.
• Validated porosity measurements using a gas pycnometer.

Main Results:

• Observed three baking stages: expansion, shrinkage, and re-expansion, with total porosity ranging from 0.145 to 0.373.
• Identified peak pore size at 20 minutes of baking (8.53 g/100 g solids moisture content).
• Found increased pore interconnectedness and permeability in longer-baked cookies, with absolute permeability between 1.75 × 10^-11 m^2 and 4.68 × 10^-11 m^2.

Conclusions:

• Porosity and pore coordination number trends correlated with cookie permeability, indicating their importance in fluid transport.
• Heat and mass transfer during baking are key drivers in developing the final porous structure.
• Controlling baking parameters based on microstructural insights can enhance industrial food processing, quality, and texture.